I walked into my bedroom and found my sister sprawled out on my bed. Nova was lying on her stomach, legs idly kicking back and forth in the air, her phone and notebook in front of her.
"Hey bro," she greeted me.
"Hey yourself," I said, shrugging out of my hoodie.
Nova had gotten into the bad habit of wearing some very, very tight shorts lately. The way she lay in my bed showed off her cute butt way too nicely, though she kindly didn't turn to look at me and gave me the chance to stare a moment before sitting on the bed next to her.
"You know you have a room of your own, yeah?" I said.
Nova shrugged. "What fun's that?"
"I mean..."
"Besides, I wanted to ask you some things."
I rolled my eyes. "Of course you do. You've been asking such weird questions lately."
"Have not," Nova pouted, acting offended. "I'm doing research. Learning. Bettering myself. These are noble endeavours."
"Last week you asked me whether you should start wearing a padded bra," I said.
"To make my tits look bigger," Nova said, as though it was perfectly reasonable.
"The week before, about what kind of shorts to wear to make your butt look good," I continued.
Nova wiggled her booty. "How are these ones doing?"
"I mean... fantastic, and I think you know that," I said.
She grinned, fully pleased with herself. "Good. I thought so."
"Why are you asking me these things though?" I asked. "It's weird."
"It's not," Nova said. "You're a boy, Sol."
"Thanks for noticing."
"And you've got relevant opinions," she said. "Plus I know when you stare at my ass, you really mean it."
"... is there a way to stare at an ass and not mean it?" I asked.
"Well, you know," she said airily. "It means more coming from you."
"You shouldn't want your brother staring at your ass," I said. "Or helping you pick out bras to make your tits look bigger."
Nova chewed the end of her pen, somehow making it look cute and naughty while she pondered. "Do you like staring at my ass?" she finally asked.
"In those shorts? Yeah."
"So we're both winning then."
"One could so argue," I agreed evasively.
Nova took the time to jot down a note in her book. Something about me, no doubt. She was doing that a lot lately. It probably made me look like a perv, all full of remarks about how I liked her butt and which bras looked best on her. Not my fault. She asked.
"You don't show this stuff to anyone, do you?" I asked. "Whatever you're writing in there?"
"It's research for making myself attractive," Nova said. "I've told you that. I don't show anyone, but I do talk about it with my friends."
"Oh god."
"What? It's useful. They benefit too. You want me to hoard knowledge?"
"How much new and fresh knowledge are you really gaining here?" I asked.
"Plenty," Nova assured me. "Like the right amount of midriff to show off to get you to peek without making Mom and Dad mad. That's useful. And that these shorts work. I was worried too tight was going to be slutty or not really look good actually. But it seems to be working out."
I blushed as I realized she'd caught me staring again. I hadn't even meant to. It just happened, the way her butt cheeks were perfectly shown off in near-skintight shorts, and the way her kicking legs kept drawing my eye. That was probably part of her experimentation too, though she hadn't mentioned it specifically.
"The shorts might be pushing it if you're trying not to get a talking to about your outfits," I said, attempting to deflect from my indiscretion.
"I think so too," Nova said, wrinkling her brow in thought. "But I've been trying out cunningly not letting the wrong people see them from behind. They're modest enough from the front." She perked up. "Plus now that Mom and Dad have taken off traveling for the summer, it's kind of the best time to try some more risque stuff out."
"You're crazy," I said.
"I'm scientifically minded," she countered.
"The Venn diagram overlaps on occasion," I said.
"Hehe, good one," she said without a hint of taking it personally. "Ooh, by the way, check these out."
I looked warily at her phone as she scrolled through a few pictures for me.
"Are these... are these just all pictures of your friends' butts?" I asked.
"In tight shorts, yeah," Nova said. "Whose is the cutest, you think? I know who I'd pick, but I want an unbiased opinion."
"This is weird, Nov," I said. "But you really want to know?"
"Of course. That's why I asked."
"Your butt is the cutest," I said.
"That's cheating!" Nova protested. "I asked about the pics."
I ignored her. I could see how obviously pleased she was with my answer. The way she beamed, the happy blush on her cheeks. The way she immediately flipped to a different page in her notebook and gleefully wrote down something she wasn't about to share with me.
Unless it was my imagination, Nova even arched her back a little more, gracing me with an ever so slightly better view of her booty while she scribbled hasty notes to herself. She was killing me, but in such a fun and thoughtful way.
"You know the danger here is I'm going to start checking out your butt more often," I said. "You're training me to misbehave."
Again I was dead positive that Nova was thrilled to hear that.
"Not my fault," she said. "But if you could possibly keep track of how often you feel that way, what I'm wearing and doing at the time, how long your gaze lingers, what--"
"I'm not doing that," I said.
Nova expressed mild frustration with that response. "Kind of a waste if we're not collecting data, don't you think?"
I tilted my head and stared thoughtfully at my sister's cute little booty. "I don't think it's a waste."
She wiggled her hips in response. "You're enjoying looking?"
"Yeah."
Nova nodded like I'd just given her an opinion on something totally innocuous. "I can work with that, I think. I can still take notes, I'd just need to know when you're looking or interested. Some way of recording what's happening."
Her gaze fell to my crotch, which all of a sudden made me embarrassed. Yes, I was getting kind of hard. Not like fully erect over my little sister or anything, but certainly having a reaction to her perfect booty.
"Don't make a note of that please," I sighed.
Nova grinned and scribbled something down anyway.
"You're going to make this weird," I said.
"You got hard," she chirped. "Not me."
"Only a little," I protested weakly.
She tapped her pen on her chin. "Can I see?"
"No."
"Please?"
"Absolutely not."
Nova turned her big, pleading eyes on me. "Even just through your underwear? It's just hard to see what's going on while you're wearing pants."
"I think that's by design," I said.
"You're making this difficult," she grumbled.
"I'm really not," I said.
Nova retreated into her thoughts, with the occasional moment of jotting something else down in her notes. I was honestly curious just what exactly she was keeping track of in there, and how much help it was actually going to be to her. To me it only made sense that something looked good or it didn't. Trying to quantify arbitrary things felt like it would be very difficult or impossible.
I played on my phone, relaxing into just sharing a room with my sister while she did her own thing. It was nice just to hang out sometimes. I could almost forget what she--
"What if I touch it?" Nova asked.
And there it was again. "No," I said.
"Without looking I mean," she clarified, as though it made all the difference.
"Still no," I said.
"Over the pants?"
"Sure."
"Really?!"
"No."
"Mean!" Nova said.
I could see her pouty face from the corner of my eye, but stayed focused on my phone.
She tried a few more angles, and it actually got pretty amusing what she'd suggest, and how increasingly exasperated she got with my refusals. There was, too, something flattering about my dick being so desired, even given the current context.
I had to admit, she got me good in the end. She shifted around in my bed quite oddly, almost like she was throwing a quiet and delicate tantrum. It wasn't that, but I had no idea what she was actually doing until she took my hand and placed it on her butt. The way she'd maneuvered her body suddenly made sense, but very little else did.
I froze, hand firmly on my little sister's ass. Her tiny, skintight shorts weren't hiding much from my touch. I could feel her pretty well, and... it was nice. Really, really nice.
"Feel free to provide any thoughts or feelings you're experiencing right now," Nova said, almost casually, but with a faint hitch in her voice that I almost missed.
"There's something not normal about you," I said.
"I mean in regard to your hand on my butt," she clarified.
"My statement is quite related to that, actually."
But I wasn't pulling away. I didn't want to. I hadn't ever wanted to fight too hard about her wanting me to check out her butt, for instance. I was even less inclined to argue about feeling it up.
She was going to let me do it, too. I could shift my hand and fingers, squeeze her ass, explore the fascinating curves, and Nova would absolutely just lie there and take notes on the experience.
At first I told myself I was just going play chicken with her. See how long and how far she'd actually let me go before she realized this was crazy. But I knew right from the start that was a lie. I knew my sister way too well for that. Not that she'd ever encouraged me to feel her up before. But if she wanted it now, it wasn't likely at all that she'd change her mind.
"You've got a great butt," I finally told Nova.
I could practically see the beaming grin on her face even with her looking mostly away from me.
"Noted," she said, happily marking that down. "Anything more specific?"
"Not that I'd care to try and elaborate on," I said.
"Sometimes I worry you don't have the true soul of a scientist," Nova said.
"I'm excellent at physics and engineering, thank you very much," I said. "Your niche applications of biology and psychology are not my strength."
Nova snickered. "Fair. Ok, let me gather some more data then."
I knew she was going to try something outrageous. Once again, I knew my sister pretty well. She had a face like she knew she was about to get away with something that she knew she shouldn't.
She went for my pants. I wasn't as surprised as I probably should have been. More fucked up was I didn't feel like stopping her. If she'd asked I'd have told her no again. Since she didn't...
I didn't know what to make of the implications there. I shouldn't be more open to things she didn't ask for. Yet much like placing my hand on her ass, just doing the thing was getting easier acceptance from me.
"Ooh, very hard," Nova cooed excitedly. "Lift your butt for a sec, let me pull your pants out of the way."
"Terrible idea," I said, even as I complied.
I knew she was going to pull my cock out of my boxers too. I still could have stopped her. I didn't.
"Oh that's nice," Nova breathed as she got my full erection out. "Fully hard, yeah?"
I nodded. "Yeah," I said, sounding a bit strangled even to myself.
Her fingers felt so good on me. Her touch was not something I should have felt. Not like that. But she had me right where she wanted me, interested and compliant. I knew I was weak like that when I got horny, I just hadn't realized that it would even work for my baby sis.
"See this is what I'm talking about," she said, running her fingertips up and down my shaft. "This is valuable information. If I can do this to you, I'm onto something.
"If you can touch me inappropriately?"
"No, silly. If I can make you hard like this. And..." Nova's eyes widened and she rubbed her thumb over the head of my cock. "And if I can make you drip like that," she finished huskily.
"Yeah, I mean precum's gonna happen if you play with me like that," I said, failing to sound as casual as I would have liked.
Nova bit her lip and kept rubbing me, delighting in each fresh bead of precum she milked from me.
"Useful information," she muttered. She seemed to be trying to convince herself as much as me.
Nova dragged her notebook over to where she could jot notes with her right hand while her left settled into a slow stroking motion intermixed with teasing the tip of my cock and greedily swiping up precum.
It was a bizarre and confusing experience for me, but one that felt incredible.
"You know you're jerking your brother off," I said in a low voice.
Nova started and glanced at me as though she'd half-forgotten I was there. She slowly grinned. "Not yet I'm not." She hesitated. "I haven't really done that though. Is it ok to practice?"
"You're... you're seriously asking that while you've already got your hand wrapped around me?" I asked.
She cocked her head, and the impish sparkle I saw in my sister's eye was not at all one of scientific detachment. "Would you like me to jerk you off?"
"Nov..."
"Sol."
I wasn't going to win a battle of wills here. It wasn't fair at all when she was still running her hand slowly up and down my cock. I still waited and let the tension build, just to salvage some kind of pride.
"Please," I finally said. "Please jerk me off."
It might as well have been my sister's birthday for how gleeful she looked. It wasn't about the handjob itself, I was well aware of that. Probably some combination of the power she had over me right now, and the information she'd gleaned about how I operated.
"That's something to explore again," Nova mused, writing her notes before focusing on my cock again.
"What's that?" I asked, hardly daring to voice the question.
"How horny you have to be to ask me something like that," she said. "From your sister of all people."
My cock twitched and spurted extra precum in her hand. She gasped and giggled and wrote it all down of course.
"Oh my god," Nova squealed. "Really?"
"Shut up! It's not a fair test," I insisted.
"Uh huh," she said, stroking me with more purpose. She gazed at me intently, waiting patiently, her eyes piercing through me. "But this is rather fascinating all the same, don't you think? And it calls my data into question if you're going to respond so positively to your sis-ter playing with you like this."
My cock twitched again in her warm little hand. I couldn't do anything about it. I had no control. She was going to think I was some kind of total perv at this rate.
"I don't think about you that way," I mumbled, face flushing embarrassingly warm. "This is not normal."
"I could almost believe that," Nova said thoughtfully. "But I also believe now that more testing is in fact required here. Because you do react to the incestuous component, even if as you claim that's not usual. Kind of a bad bro-ther, aren't you?"
I moaned helplessly as Nova kept up her sensual torment. I wished it wasn't so hot when she reiterated our sibling status, but it actually fucking was. Her stupid games, her stupid tests, they were doing things to me. Of course they were. I'd have a reaction to any girl in bed making me check her out, grab her ass, and lie back while she played with my cock.
But yes, there was some specific thing about her being my sister. I'd only be lying to myself to keep pretending otherwise. I just didn't like it. It was embarrassing.
It wouldn't have even been so bad maybe if she'd been a hot older sister. Even a sexy mom. Those could have been excusable. Getting this way for a cute and mischievous little sis reflected poorly on me, I felt.
But I couldn't stop her stroking me. I didn't want it to end. She felt so good. So good. My baby sis's handjob...
"I don't want to spoil the result," Nova said softly, "but then again I didn't think to time it properly anyway this time. I think you should cum for me, Sol. Do you want to cum?"
I whimpered. "Yesss."
"Good. Then cum for me, ok?" Nova was feeling the horniness of it all too. I knew she was. But she was still very much in charge. She smiled wickedly at me. "Cum for your sis-ter?"
I did, I came for her. Exploded and made a mess all over myself and her hand. She kept stroking me, giggling madly at the hot cum getting on her, but not letting it stop her. I had to eventually nudge her hand away when my orgasm was well and truly done with.
Nova stared at the cum on her fingers, and only slowly and absently fumbled for her notebook. I had no idea what she still felt she needed to record from this event, but she was dedicated, I had to give her that.
"That was... useful," Nova said, hesitating like she'd temporarily forgotten how to speak.
"It felt really nice," I said.
"Yeah?"
"Yeah."
"You think other boys would like it too?" Nova asked.
"Is that a serious question?" I asked.
"Yes, of course."
I laughed and shook my head. "I can't with you right now. But like, maybe if you jerk a boy off, don't follow up with asking about what other boys might enjoy."
Nova nodded seriously and started writing again.
"Don't write that down," I sighed. "Oh nevermind. You're not going to listen, are you?"
"I serve a higher calling," she informed me.
"I don't know that handjobs are a higher calling," I said. "Although I suppose that's a religion I could get behind."
"Not that kind of higher calling, silly," Nova said. "Now if you'll excuse me."
I watched my sister patter out, somehow still glued to her cute, tight little booty even after cumming.
"I wasn't keeping you here," I muttered after her. Though in fact some twinging part of me wanted her to stay. I was not about to admit to such things right now. She'd only write it down, probably.
****
Nova didn't do anything weird for the rest of the week. Instead of relief, or indeed indifference, I found myself fantasizing about her butt and thinking about the feel of her soft hands on me while I was jerking off. That wasn't good. She'd be so smug if she knew.
It was probably for the best if that event had been a one-time, crazy thing anyway. It wasn't like incestuous handjobs were encouraged in society. Even if they did feel really good.
I didn't think anything of Nova inviting Skye, one of her best friends, over. That was a perfectly normal thing. I liked Skye well enough, as far as my sister's friends went. She was relatively fun and polite.
She also had a cute butt, as I slowly realized. I may not have really looked before, and perhaps it was due to Nova putting my mind onto this sort of thing. After checking out my sister's butt, checking out her friend was a step more behaved if anything.
It took embarrassingly long for it to dawn on me that this was a deliberate thing. Skye was wearing small, tight shorts, very similar to the ones Nova wore so often these days. Very unlike her usual. And the way she kept blushing and smiling around me kind of confirmed that something was up.
It was all so obvious once it clicked. This was Nova experimenting on me again. She didn't actively write in her notebook where I could see, but I was sure she was doing so. I wondered belatedly if Skye had been in those butt photos my sister had tried to get me rate previously. Most likely she would have been.
I took an opportunity when Nova wasn't in earshot to question Skye about the situation.
"You know what Nova's up to, yeah?" I said.
Skye flushed and wouldn't quite meet my eye. "What do you mean?"
"With the shorts and all. In front of me."
Skye squirmed. "She said you'd like it," she finally said, blushing even more furiously red than before.
"She's not wrong," I said. "You've got a cute butt."
I thought Skye might just melt away right there. More than just her butt was cute, as it turned out. The freedom to notice these things was kind of fun.
"Really?" she squeaked.
Yeah," I said. "So you want me to check it out, huh?"
"Um... well Nova wanted to experiment with that," Skye said evasively. "See what you'd do..."
"And what do you want?" I asked.
Skye looked away and wouldn't answer.
"Do you just want to see what I do?" I prodded gently.
She nodded. "Nova said it would probably be fun. And it wouldn't be a big deal, because you know, you're her brother. It's just... you know, learning. Science. Figuring stuff out."
"Yeah, right. Science," I said.
I shifted beside Skye and let my hand drop to her butt. She whimpered and didn't seem to know what to do. She very much didn't pull away though.
She slowly untensed, and perhaps even pushed back against my touch. She didn't seem to know what to do with herself, but she was here for the fondling.
I took Skye to the couch and sat down. I let her curl up with me in a way that left her butt sticking out where I could freely grope it some more.
Nova materialized almost immediately after Skye and I had settled in. She was so subtle I didn't even register her presence at first until I heard the scratching of her writing in her notebook.
"Don't let me distract you," Nova said as I turned my gaze toward her. "Just keep doing your thing."
"You're actually insane," I informed her, knowing I might as well hurl insults at the ocean for all the good it would do.
"Genius and insanity are often conflated," Nova responded primly. "How would you say Skye's butt feels compared to mine?"
So she'd shared that part with Skye already. Somehow I'd suspected she would have, even though anyone else probably would have been more secretive about getting felt up by her brother.
"I don't know how to answer that," I said. "Nor am I sure I want to."
Nova sighed. "You're exasperating sometimes, you know that? If you need to compare directly, you can just ask."
It wasn't what I was angling for, actually, but maybe I should have been. Nova curled up with me on my other side and made sure I was able to fully cup and squeeze her ass as well. Getting sandwiched between the two girls with freedom to feel up their butts all I wanted was cozy and delightful.
Nova jotted down notes intermittently--while making sure I couldn't see what she was writing of course--and seemed totally at ease with letting her brother grab her butt in front of her friend. Skye remained cute and shy about the whole thing, though admittedly didn't seem any more bothered about me groping my sister than Nova herself was.
"So which do you prefer?" Nova eventually asked. "And how significantly would you say the incestuousness impacts your decision?"
"Has she always been this way and I just haven't noticed?" I asked Skye, ignoring my sister.
Skye shrugged. "A little bit. She's been different lately with trying to figure out how to quantify and acquire hotness."
"It's a valuable commodity in today's market," Nova said. "And useful research in any case. My butt or Skye's?"
I sighed. "It's still hard to actually pick, you know. There is a thrill to you being my sister, but also a novelty to Skye since I haven't felt her before."
"Hm, equivocating still, but actually a good point," Nova said, wrinkling her nose cutely in thought. "Too many variables is part of the problem, I think."
"I also kind of don't want to say the wrong thing or possibly answer at all," I said, "lest I lose access."
Skye giggled and clung tighter to me. I wondered if she had some sort of crush on me that was having a chance to be explored now. Or maybe, like Nova, I just represented a relatively safe person to try some stuff out with and she was enjoying herself underneath her embarrassment.
Even Nova seemed to enjoy my admission, though it thwarted her research.
"Engaged in thoughts and actions to acquire more time with our booties," Nova said thoughtfully. "That's good actually. Maybe I need to start being less direct in my questions." She looked at Skye. "Looking at the things Sol desires or asks for might get us better data than asking him to rate experiences. He hasn't been great at that so far."
I frowned and pinched Nova's butt pretty hard. She yelped and pouted at me while Skye just giggled some more. Skye seemed to be just having a nice time without all the distraction that Nova was providing herself.
Nova retaliated by pressing her hand firmly against my crotch, catching me off-guard and making me gasp at the sudden pressure.
"And that," Nova said gleefully. "Can't equivocate out of these erections so much, huh?"
Skye's eyes went wide. "He's hard."
"Yeah," Nova said, rubbing my cock through my jeans. "Check this out."
My sister worked my pants open and pulled them down, apparently not feeling the need to ask me first. She and Skye both stared fixedly at my cock, and Nova was more delicate about tugging my boxers out of the way too, unveiling me properly.
"Oh, he's very hard," Skye said breathily.
"Yeah," Nova said, grazing my shaft with her fingers. "It's pretty fun when Sol's like this." She bit her lip. "At least, that's been my limited experience so far."
"You really... really did this before?" Skye asked.
Nova nodded. "I told you."
"Yeah but... your brother," Skye squeaked.
"I think he likes it," Nova said conversationally. "He likes his little sister touching him, don't you Sol?"
My cock betrayed me again with an obvious twitch as Nova teased me.
Nova laughed. "I get much more direct results from this," she said, lightly grabbing my cock. "Want to see how long it takes him to cum?"
Skye grinned shyly and nodded.
Nova gazed at me with false innocence. "Would you like that, big brother? You want to see if your sis-ter can make you cum again?"
I groaned and squeezed her ass hard. "Don't say it like that."
"But you're so twitchy and precummy," Nova taunted. "You liiike it."
She stroked me up and down, enough to feel good and keep me from protesting. She very obviously delighted in the reactions she got from me, and I could see her filing them away to be written down when she had her hands free again.
I kept feeling her and Skye's asses while she jerked me off. Nova was only teasing me yet, but still felt great and got plenty of reaction from my cock.
Skye was entranced, watching Nova play with me even more closely than I was. I didn't think she realized how interested and horny she appeared just then.
"How badly do you want me to take care of this?" Nova asked, and I could hear in her voice that it wasn't all just scientific interest.
I hesitated, not wanting to move, but feeling like we probably should.
"Let's... go to my room," I suggested.
Skye's eyes widened like the idea shocked her, but she didn't disagree.
Nova considered thoughtfully, then nodded.
We ended up in my bed, my pants totally off, the two girls lying down facing my cock. Nova had her notebook with her and scribbled in it before returning her hand to me.
Without making any kind of deal of it, Nova scooted herself around to make sure I could reach her butt while she stroked me. I accepted the offer.
"This is the experiment for today?" I asked.
"Yeah," Nova said.
"Two girls?"
"Changes things, doesn't it?"
I eyed Nova's butt, then Skye's. "It does," I agreed. "Shouldn't you give her a turn too though? You know, for science?"
Nova twitched back, hand leaving me. "Oh, right," she said. "That's true, you should try for a bit, Skye. I need to keep notes anyway."
Nova appeared slightly disappointed to release me, though that may have been wishful thinking. Skye looked excited but nervous.
"How do I..." Skye said.
"Just grab him and move your hand," Nova said. "I made him cum pretty easily last time."
Skye giggled with nerves and interest as she took hold of me. "Must be nice having a brother to let you try stuff on."
"This is a new thing," I said, feeling the need to make that known. "Usually this doesn't happen."
"Oh," Skye said, already enthralled by my cock again as she moved her hand up and down. "Too bad."
I looked at Nova, but she was no help. The two of them had such a warped view of things all of a sudden. Or maybe they had for a while, for all I knew.
And yet... here I was letting my sister and her friend play with me, experiment on me, and I was enjoying it. Enjoying it way too much. So what did that make of me in comparison?
"Don't you have a brother?" I asked Skye.
She blushed, but for some reason tightened her grip on my cock.
"Yeah," Skye said. "But not one who'd let me do this. Nova's lucky."
Nova got the faintest of self-satisfied smirks on her lips. I wouldn't have even noticed if I didn't know her so well.
"I might be kind of lucky too," I admitted.
Nova's smile grew more prominent. "You do enjoy this, don't you," she said.
"I think you know I do," I said.
"I do," my sister said. "It's nice to hear you say it. In detail, when possible."
"Right," I said. "The data."
"The data," Nova confirmed.
"But arguably," I said, "if you and Skye are going to be letting me feel you up and jerking me off until you have enough data, I might be better served by withholding."
Nova nodded seriously and noted something down. "Attempting to prolong the experiment. So you're quite into it now. Would you say it's more fun with more than one partner at once?"
I glanced at Skye. "I might say that," I said. "Probably... probably we need to try more times with just you, and with both of you. You know, to really compare."
They both seemed pleased with that idea. Which was crazy. The reality of being able to suggest something as ludicrous as that and get positive reception for it was brand new to me, and likely to go to my head at this rate.
I kept squeezing Nova's butt as Skye jerked me closer and closer to completion. All three of us were blushing and flustered, and all trying to hold it together as best we could. I even caught Nova forgetting her notes at times and just staring at my cock with a hungry expression, though she'd eventually remember she was meant to be researching.
"You're gonna make me..." I moaned.
Skye's eyes flashed. "Are you?" she asked breathily.
I nodded.
"Good, good," Nova said. "Keep stroking. Make the cum come out."
Skye nodded seriously, and her tongue poked out the corner of her lips rather cutely as she kept focus on getting me off.
She got even cuter when cum erupted around her fingers, making a mess everywhere. Skye squealed and giggled, but kept milking out more cum until I was spent.
Nova delightedly noted it all down, including sticking her fingers in some of the mess and rubbing my cum thoughtfully around like she could determine useful information from its consistency.
"Thanks Skye," I said. "That was nice."
Skye beamed shyly. "I did ok?"
"Yeah of course," I said. "I came, didn't I?"
"I don't really do a lot of this stuff," she said. "It was... easier than I thought. And kinda fun."
"It is, isn't it?" Nova said. "I was kind of worried too, but it's not such a big deal. At least with Sol. He makes things pretty easy once he stops being stubborn."
I pinched Nova's butt, making her yelp and glare.
"A certain hesitation toward being inappropriate with my little sister is not being stubborn," I insisted.
"It's not inappropriate if it's for science," Nova said. "It's not like it's actual incest."
Skye giggled at the word 'incest,' as though that was funnier and more scandalous than the actual sisterly seduction she'd already been witness to. I had to worry slightly about the two of them.
"I think it might still be, actually," I said.
Nova cocked her head. "Well in that case I think you're into it."
"I mean, I wouldn't say that," I protested.
My sweet, considerate sister stared at me a moment, almost issuing a challenge with her eyes, then reached out and grabbed my cock. It was soft and messy with cum, but she played with it and had it filling her hand back out in no time.
"You sure about that?" Nova asked. "You don't like when your baby sis-ter does this stuff to you?"
I whimpered rather embarrassingly. I wanted to be able to tell her to stop. To not fall for her tricks, but part of me was already noting how easy it was to get her to put her hand back on me. I didn't even need another cum right now, and yet I fully was on board within seconds.
"Maybe it's nice," I hedged.
Nova scooted around to lie between my legs and watch me while she played with my cock. "Maybe it's nice? You can do better than that."
She had me there. Now that she had me going again, I was hesitant to argue and make her change her mind. Not that I thought she would.
Skye had jerked me off, which in some undefinable way made me feel like Nova had something to prove now, I just wasn't sure to whom exactly. But she wanted to make me cum too. I was sure of that. I wanted it as well.
"Your hand feels really good," I said, giving Nova what she wanted, but not stopping there. "Your hand feels really good on your bro-ther's cock."
Nova made a small, helpless noise and ducked her face away from eye contact. She liked me saying that more than she wanted to admit. I knew the feeling.
"Such a good sister," I added.
Nova growled in her throat, either annoyed or horny, or most likely both. She kept stroking me, not faltering.
My second handjob of the session felt very good and not nearly as urgent since I'd cummed already. I wanted to enjoy this. I didn't have either girl's butt in easy grabbing range, but I was able to snake my hand around Skye's waist and pull her back toward me.
Skye was shy about being moved closer, but made herself comfortable against me while we both watched Nova. I let my hand wander up her shirt, waiting to see if she'd protest. She didn't. She even moaned softly as I got to her tits.
"You like having something to play with," Nova said, not making it a question.
"I could say the same of you," I said.
"This is not the same," Nova said. "This is research. For a purpose."
"Tell me you aren't enjoying it though," I challenged her.
"Oh whatever," Nova said. "Just shush. Let me focus."
I grinned at her even though she had her head down, staring at my cock as her hand moved up and down my shaft. She was enjoying herself. That made it better as far as I was concerned. It was more fun if everybody was having a good time.
Skye was getting very squirmy the more I played with her tits. She kept squeezing her thighs together, or reaching down with a stray hand before catching herself. It was exciting to think that she wanted to masturbate but didn't actually dare.
It was subtler, and I almost didn't catch it, but Nova's hips were going too. It was only a small motion, but she was definitely grinding against the bed as she stroked me. My sister getting horny from teasing me and playing with my cock. It was delightfully fucked up.
"Do you want to touch yourself?" I eventually asked Skye, once I'd built up the nerve to broach the subject.
She gasped and squirmed in my arm. "I don't know. Maybe."
Nova grinned and pretended to ignore the exchange.
"Do you want me to touch you?" I asked, pushing further.
Skye whimpered and looked to my sister for help.
Nova smirked at Skye. "Well, do you?"
"That... that wouldn't be ok, would it?" Skye asked.
"I'm into it," I said.
"Nov?" Skye asked. "He's your brother..."
Like Nova had exclusive claim to me because of our sibling status. Then again, that was weirdly fucking hot to think of actually.
Nova, running her thumb back and forth over the precum at the tip of my cock, gave it some thought.
"It wasn't the way I expected today's research to go," Nova said. "But that sounds like it could be quite interesting. Try to remember details for me later, ok? I don't feel like anyone's going to be taking useful notes for a bit."
Skye nodded, shy but eager. I let my hand drop experimentally from her tits to her tummy, then down across the front of her shorts. She pressed against my touch, sighing contentedly at the contact.
"Take your shorts off," I said.
Skye blushed, but wriggled out of her shorts for me, leaving her in some rather soaked panties.
Nova watched, curious and interested. The handjob she was giving me had truly become her just playing with me. No real attempt at getting me off. It was a pleasant feeling that would eventually be too much, but for now was enjoyable and keeping me horny enough to push my luck.
I rubbed Skye over her sodden panties, reveling in the small noises and involuntary movements I got from her. I didn't have a plan to start with other than that. Just rub her and see what happened.
We made a twisted and beautiful tableau, I thought. Trying things out, finding out what felt good, enjoying each other. Not exactly what my sister had intended, but all deriving from her inquiries in some fashion. If she'd wanted to experiment with sexual attraction and interest, this was certainly a good result for her.
I still thought things were simpler than she made them out to be, and sometimes things just happened the way they happened, without data and trial runs to back them up. Then again, maybe things happened because of her strategically getting me horny in the first place. Something to consider.
Skye moaned louder as I slipped my fingers under her panties. It seemed like she was happy for me to have free rein with her pussy right now, at least with my hand. More than that would probably be excessive, probably would mess with the casual sexual energy of the room. But fingering her was very on.
"Are you enjoying yourselves?" Nova asked in a mildly amused tone.
"Of course," I said, adding a little moan as my sister gave a flourish of her hand over the tip of my cock, then stroked back down again.
Skye whimpered cutely and nodded.
"That's good," Nova said. "Because I want you to cum, Sol. Cum for your sister." She bit her lip. "And Skye, if you cum, that's going to be interesting too."
Skye nodded even more eagerly. She wanted to. I wanted her to as well.
"What if you tried licking it?" I asked Nova.
She cocked her head. "Oh really?"
"Well... just to test it," I said.
"Uh huh. You want your sis-ter to put her mouth on your cock, huh?"
I groaned and twitched in Nova's hand. "You gotta stop saying things like that," I protested.
"You liiike it," Nova teased.
"I think you like that I like it," I countered.
She shrugged. "It's kinda fun."
Nova kept jerking me off, then eventually did lean down and swipe her tongue up my shaft. Perking up at the way I moaned for her, she did it again, and again. Giving me licks in between stroking me, or flicking her tongue across my precummy tip while jerking me firmly.
"Cum on her," Skye urged, whispering in my ear. "Do it."
I closed my eyes, nodding, then opened them again, watching my sister directly. I was close. So close. And Nova was absolutely intent on making me cum. There was something insanely hot about that, even outside of just the physical sensations.
My first spurt of cum caught Nova across her tongue and chin. She stayed frozen for long enough to get a second shot, then pulled back and let the rest of the mess fall on me and her fingers.
"You... came on me," Nova said, sounding somewhat dazed.
"That was bound to happen," I said.
Nova gave a small, secretive smile and reached for her notebook. I tried not to sigh out loud about it, but honestly she'd made me feel so good that whatever she felt she needed to do right now was probably well earned.
"Oh god," Skye whispered. "Oh wow, oh god."
My fingers had been probing inside her, as well as rubbing around her clit on the outside. Skye pushed my fingers a little deeper into her, held them there to make sure I wouldn't move, then started rubbing her clit for herself. I let her use me as a prop while she got herself off, apparently quite turned on by me cumming on my little sister's face.
Nova noted some things down and then, I could only assume, started taking some observations on Skye's journey toward orgasm. That went in a different section of the notebook. I had no idea what it was for, but then again this was all my sister's unique brand of research in the first place. It could be for anything.
Skye panted softly after getting herself off and curled up against me, nestling as cozily as if we'd cuddled many times before rather than being recent strangers to any sort of intimacy with each other.
"This," Nova said, flipping slowly through her notes, "has been a productive day."
I snorted. "That's one word for it."
"You disagree?"
"No. Just... what if you used words like fun or intense or horny?" I asked.
Nova nodded agreeably. "Those are pertinent choices also."
She looked down at her hand, seemingly recalling the cum on it for the first time since it had landed on her. She touched her face as well, then experimentally licked at the cum on her fingers. After a moment's hesitation, she tasted some more.
"Not bad," Nova decided, noting this down as well. "Not amazing, but not bad."
"Pretty hot though," I told her.
She paused. "You find that enticing?"
"Yes," I confirmed.
Nova grinned. "Thank you. All I'm asking for is some data to work with here and there."
Skye giggled softly. "What about you, Nov? Did any of that get you horny?"
Nova actually blushed this time and didn't answer straight away.
"It did, didn't it?" I teased.
"Maybe some," Nova said defensively. "Don't worry, I'm recording that as well."
She wouldn't quite look at me, and she was pretty fidgety.
"Should we, perhaps, make you cum now too?" I inquired, trying to sound casual about it.
As calmly as I spoke, it still flustered Nova. She didn't seem to know how to proceed, which was both fair and incredibly cute.
"That might be nice," Nova finally said. "You... you want to?"
I smiled. "Yeah."
"Get Sol to put his fingers in you," Skye advised, still clinging to me. "It feels really good." She started to reluctantly pull away from me, but I held her where she was, which she happily accepted.
Nova took her shorts off a bit shyly, revealing panties every bit as soaked as Skye's had been, if not more so. I marveled in awe at how they clung to my sister's pussy, showing off the shape of it even if I couldn't see it directly.
She crawled forward, finding an appropriate spot next to me, and guided my free hand into her panties. She was so wet and needy, and moaned as I rubbed her wet little cooch.
I kept rubbing Nova until she urged me to press my fingers inside her and she started rubbing her clit, much as Skye had shortly before. It was different, of course, having fingers inside my sister like that. Different and more intense.
"That's right," I urged gently. "Cum for me. Cum for your bro-ther."
Nova whined and shook her head, flustered. But she panted louder and her fingers blurred faster. I wasn't the only one who got a thrill out of the sibling aspect of this. She most likely didn't want to admit to it any more than I did, but when we got horny enough there really wasn't any hiding it. It was at least more balanced if it worked for both of us.
"You two are crazy," Skye whispered. She bit her lip. "But that's really hot too."
Nova whimpered and rubbed herself, and eventually came moments later. I watched all the tension and need drain out of her in a relaxing and satisfying way, and my sister nodded like she'd done a good job that needed doing.
She leaned back against me afterward. Unlike Skye, all curled up with me, Nova had her back to me, and had her legs up to rest her notebook on. She still let me hold her with my arm around her and my hand up her shirt on her tummy, but her focus was on taking notes again.
"Make sure you write down that you get turned on playing with your brother," I teased her.
Nova snorted in exasperation. "This isn't about me. And anyway, that was only because it caught me by surprise."
"Maybe it should be about you," I said. "Seems wasteful figuring out how to get someone interested and excited and ignore what you actually want, doesn't it?"
Nova hesitated. "I suppose that's true. No good doing all the work for someone who doesn't do it for me."
"It's a good point," Skye murmured, happy and sleepy on my shoulder. "Gotta find the right boy first, then worry about how to get him."
"Ugh, so complicated," Nova complained, starting a brand new section in her notes. "How does anyone ever figure everything out?"
"I think mostly they don't," I said.
"Well that seems chaotic and painful," Nova said.
"Yeah," I said. "That sounds about right." I shrugged. "My experience dating has been chaotic and painful, mostly."
"See? So acquiring knowledge and experience is needed first," Nova insisted. "So we can be more deliberate and resourceful."
I slid my hand up to grab my sister's tit. "Or just see what happens and slowly figure out what works and doesn't work," I suggested.
Nova blushed and moved her arm to trap my hand where it was on her chest. "Sloppy research, you mean. No thanks. I'll do it my way."
I ran the fingers of my other hand up and down Skye's spine. She purred softly, eyes even closed now as she cuddled against me.
"I suppose I can live with that," I offered magnanimously.
"Me too," Skye mumbled cozily.
"Good," Nova said seriously. "I have lots of pages to fill yet." She paused. "Might need a bigger book, even."
****
The next night, as I was getting ready for bed, Nova slipped into my room. She paused at seeing me with my shirt just pulled off, but then padded over to sit on the edge of my bed, ever-present notebook in hand. She wore a loose sleep shirt with bare legs underneath.
"Did you masturbate today?" Nova asked.
"Your small talk needs work," I told her.
She said nothing.
I sighed. "No. I was probably going to before bed. Helps me sleep, you know?"
Nova nodded. "Makes sense. I find that too. But I kind of realized I might get better data if you masturbate less. Or not at all. So we know when you get horny, and how much stimulation and release you're looking for, and how that impacts your interest in me. Stuff like that."
"My interest in you, huh?" I said.
"In girls I mean," Nova said, looking away quickly. "Just, you know, with me for now. While we're researching."
"You enjoy how turned on the 'sister' thing gets me though," I said.
"Yeah well... it's funny, isn't it?" Nova said. "And it's very possible that some other cute and interesting boy might like that kind of stuff too at some point, so it's not like it's without value."
"Ah, very sensible," I said, meaning nothing of the sort. "Do you have panties on under that shirt?"
Nova cocked her head curiously at the sudden shift in conversation. "None of your business actually," she grinned.
"Ha, fine. I think you like that your bro-ther is interested in messing around with you though," I said.
"Sol!" Nova protested. "Behave."
I shrugged. "Why?"
I sat next to my sister and let my hand slip under her shirt. She had panties on. It would have been quite a leap for to have gone without, but I admitted a small disappointment about it all the same. Nova was really throwing me for a loop lately. Going from purely platonic baby sister to someone I hoped would visit me without any panties on.
Nova was flushed though. Her cheeks red, and her skin warm under her shirt.
"Not all the data can be about sibling kinks," Nova said, almost sounding like she believed herself. "That's only going to get me so far with attracting a boyfriend."
"But you do have that kink," I pressed.
"You really want to get into which of us has it worse?" Nova asked. "It doesn't reflect well on either of us, in some ways."
I mulled that over. "Perhaps," I said. "But it doesn't mean anything, right? And not like anyone has to know."
"Skye knows," Nova said.
"Well yeah, but--"
"And Aurora."
"Aurora! How many of your friends are you--"
"Just them," Nova said placatingly. "We've been trying to figure stuff out together. Sharing information and stuff. No one teaches you how to attract the right sort of boys, you know. To find someone who likes you and will treat you well. We're just helping each other out."
"I mean right now you're just learning how to seduce your brother," I said. "Which I appreciate, but it feels like you're limiting yourself."
Nova shook her head. "No, see, this is perfect. You're not someone who's going to be a problem long term. Just someone to mess around with for a while. And I know you, and know that you will treat me well, and be kind to my friends for that matter. And if I can even get my brother to like me in a sexual way... that feels quite promising."
"Are you... using me?" I asked. "Am I being used?"
"Kinda, yeah. Do you mind?"
"Are you going to jerk me off before bed?"
"Hopefully," Nova said.
"Then I think maybe I don't mind," I said.
I got into bed with Nova, hesitating only a little about getting fully naked. It wasn't like having a shirt or not made a big difference, but the weight of full nudity with my sister still meant something. Once she got cozy next to me it all felt good anyway.
"There's an argument, I suppose," Nova mused as she played with my cock and got it hard, "that if you make this too easy for me I won't really learn as much."
"Maybe the lesson is things aren't as difficult and complicated as you think they are," I said.
"Actually possible," Nova conceded. "But the data doesn't back that up so far."
I moaned quietly as my little sister's soft, warm hand stroked softly up and down my cock.
"We better do more research then," I said.
"See? Now you're getting it."
Nova jerked me off while snuggled up against me. She seemed happy where she was, and I was happy to have her there. It got me thinking about removing her clothes though.
I settled for slowly working my hand under her shirt. The way she lay on my arm restricted my movement and options, but Nova just smiled as I put my hand on the small of her back or toyed with the edge of her panties.
"This is nice," she finally said.
"Agreed," I said.
"You know, I was worried sex stuff was going to be horrible and stressful," Nova said.
"Were you really?" I asked.
"Well... maybe not horrible. I knew it could feel nice. But stressful, sure." Nova lay her head more on my chest and watched her own hand moving on my cock. "But this is just... comfortable. Pleasant."
"It could be more exciting if you wanted," I said.
"Hehe, I'm sure it could. But no, not right now. I'm enjoying this." Nova looked at me. "It's kinda sexy you being naked though. I might want more of that."
I bit my lip, enjoying the way she gazed into my eyes just then. "You like that, huh?"
Nova shrugged and lay her head back down. "Well, you know, it's easier to try things out."
"You said it was sexy," I said.
She was quiet a moment before replying. "It is," she admitted. "I've never been in bed with a naked boy. I think I like it. You know, if it's the right boy."
"And your big bro happens to be, huh?" I said in a low, teasing voice.
Nova squirmed. "For some purposes, yes."
"You think your brother's sexy."
"Sol! Behave!"
I chuckled. "The sheer irony of you telling me to behave while you're jerking me off."
"Hypocrisy, actually," Nova said.
"Still," I grinned, "you think I'm sexy."
Nova gave me a light bite on my nipple. It was probably meant to chastise and silence me.
"Ah!" I gasped. Then, "do that again?"
Nova buried her face in my chest. "Solll! You're so horny!"
"That's what you wanted," I said.
"Yeah, but..."
Nova nipped at me again. I flinched, giggling at the sensation. I got her back by slipping my hand fully into her panties, grabbing a handful of my sister's ass, then giving her a sneaky pinch.
"Ow, hey!" Nova squealed. "You told me to!"
"I know," I said, daring her with my eyes to do it again.
Nova let go of my cock and pinched my side where I was more sensitive. I laughed and flinched away from her attack. I tried to retaliate, but my little sister was in full dodging mode now, wriggling around out of any attempt at getting hold of her.
We ended up wrestling around together, which held whole new dimensions for the two of us given how sexual things were. Nova was slippery, but not strong enough to really pin me and make it stick. She did, however, pretty quickly realize that she had a new and effective weapon against me, which was to press or rub part of herself against my cock. I couldn't fight against that.
"Are you going to be good?" Nova asked, finally sitting atop me, her cute butt pressed against my erection, slowly grinding back and forth in small but significant motions.
"Define good," I said.
"No pinching me," she replied promptly. "Unless I ask."
I nodded, grinning. "Deal."
Nova nodded back, then bit her lip and leaned down to me. She tugged the collar of her loose shirt away from her neck, baring one of her shoulders.
"Try... just try biting me too," she said. "Just a little."
I nodded and pressed my teeth to my sister's pristine shoulder, nipping at her hard enough to leave a small mark behind. She gasped, thought about it, then leaned closer.
"Again," she urged.
I bit Nova's shoulder again, in a different unblemished spot. She sighed this time and relaxed down on top of me.
"We might need to experiment with that more," she purred.
"I think so," I concurred.
Nova resumed stroking my cock, and I got her panties down to her thighs, taking her ass as my plaything. She bit me a few more times, giggling at my gasps and the way I twitched in her hand every time.
"Cum for your sis-ter," Nova urged me as I got close.
I groaned. She was practically training me to cum to reminders of our sibling bond. She was going to keep doing it too. I could tell.
"You could... just tell me... to cum," I panted.
"You like it more this way," Nova said. "Cumming for your little sis-ter is hotter. Try to tell me it isn't."
I whimpered and shook my head, and seconds later was cumming over my baby sis's hand, just like she wanted. Fuck, it was hotter cumming for her, just like she said. I couldn't pretend it wasn't.
I passed Nova some tissues so she could clean us both up, then she turned on my bedside light, curled up next to me, and thoughtfully jotted down important information in her notebook.
"You're writing down that you like being bit, right?" I said, kissing her shoulder where I'd left marks.
"Of course," Nova said. "You think I'd ignore something like that? I'm shy and inexperienced, not ignorant."
I laughed softly, knowing full well how much more of a sin the latter was to her than... well, most anything else, really.
I nibbled on her shoulder some more, seeing how distracting I could be. I worked my way to her neck, giving her a few calculated bites just to see.
Nova tried to ignore me, to focus on her notes. She got squirmy though, and she went long seconds without writing a thing.
"Play with me?" she finally asked.
"Your pussy?"
"Yeah. You got me all wet now," she said.
"You've been horny for a while," I said.
"Maybe. Just... if you're gonna turn me on like that..."
"Any time," I whispered, moving my hand between Nova's thighs. "You can just ask."
"It's better if I find what turns me on naturally," Nova said. "It's better research than just, you know, asking."
"Well we found that out tonight, didn't we?" I said.
Nova perked up. "Oh yeah, true. We did pretty good tonight, huh?"
"I'd say," I said.
I removed Nova's panties entirely. She didn't let me flip her shirt up, and I still didn't get a direct look at her pussy, but she let me play with her as much as I wanted. She was so wet. Just as horny and flooded as could be.
"Some might say asking for what you think you want is a pretty natural way of finding out what you like," I said thoughtfully as I fingered my baby sister's hot little pussy.
"I wouldn't have thought to ask you to bite me," Nova argued.
"Fair. But you could ask for other stuff," I said.
She shrugged. "We'll see."
I gave up for now. I kind of understood where Nova was coming from. It was hard to know what you liked until it happened.
At least some things were obvious. Like her playing with my cock, or me playing with her pussy.
I was really, really enjoying her pussy. It was fun getting to rub it, and slip fingers inside. Nova made such cute faces and noises as I made her feel good.
I waited until Nova was getting really close to cumming, then gave her an intent look. "Cum for me, Nov. Cum for your bro-ther."
She squirmed. "Solll!"
"Cum for your big brother, ok? Be a good little sister."
"Ah! Too much. Too muuuccch!"
She came on my fingers, making me feel like it wasn't too much at all. I wanted her to cum for me, and she did. It seemed appropriate to me.
"That's too much," Nova repeated, clutching at me afterward.
I rubbed her thigh. "I don't think it was. I think you liked it."
"I did like it," Nova said. "But you're going to think I enjoy the incest part way too much."
"You did kinda start it," I said.
"Well... maybe." Nova bit her lip. "And it is fun. Just don't overdo it."
I grinned at my sister. "Just a little incest as a treat?"
"Hehe, yeah. As a treat."
We rearranged ourselves, getting cozy again with Nova propping herself against me so she could make her notes. I held my arm around her and waited until she let me turn out the light again. She didn't leave for her own bed, and I wouldn't dream of suggesting it. I wasn't prepared to spoon her or anything, but having her next to me was nice.
****
Nova was extra chipper the next day. I thought sleeping in the same bed might be weird afterward, but it felt normal even though it really wasn't.
We didn't end up with much of a chance to hang out that day, and for all I knew my sister wanted a break before being naughty again anyway. I couldn't stop thinking about her though, and sneaked into her bedroom that night instead of just being patient.
"Hey! I was changing," Nova protested as I slipped into her room.
I'd caught her with her shirt off, but bra still on.
"That's ok. I'll wait," I said, hopping into her bed.
"I knew you were going to get to be a nuisance sooner or later," Nova sighed.
I grinned at her. "Your tits look nice in that bra."
Nova's hand flew up instinctively to cover herself more, but she caught herself and dropped it back down. "This isn't even a sexy bra."
"It's working for me," I said.
"You know, if you're going to be too horny all the time, it's going to affect my ability to get any meaningful data," Nova said.
"Maybe it just means you're better at attracting attention than you thought," I suggested.
"Or maybe I've trained you that if you compliment me, you get handjobs," Nova said.
"It can be both," I said. "Speaking of which..."
"You want me to jerk you off?" Nova asked.
"Yes please!"
She made an exasperated noise. "Ok, well I want to anyway. I think I'm getting pretty good at it."
"You are," I confirmed.
"But can we at least get some quick research in first?" she asked.
"Probably," I said. "It usually goes well for me."
Nova nodded. "That's true. I'm going to need you to try and be objective though. I really do have sexier underwear. I'm going to try some options on, ok? And I need some actual answers about what is more attractive and enticing."
"Deal," I said. "That's a sacrifice I'm willing to make."
Nova rolled her eyes and opened her underwear drawer. "Don't look until I say, ok? And... if you want to take your things off..."
I was already slipping out of my shirt and boxers, leaving myself naked in my sister's bed. That was a bit of a weird feeling, but I was far more interested in Nova than in my own slightly out of place feelings.
I watched Nova slip out of her jeans. Her cute little butt looked really good just in panties. She slipped out of those too, and into what was admittedly a noticeably sexier pair. She did the same with her bra before turning around.
"Ok, what do you think?" she asked.
"Hot," I said.
She glanced at my cock, which was halfway to life already. "I know that's not a lie," she said. "But also not very specific."
"I'd say really hot," I said. "But I feel like there's something better coming, and I want to save some options."
"You're so very hopeless as a research assistant sometimes," Nova grumbled, turning around and unhooking her bra.
I could tell she was pleased though. She craved attention and compliments, even if ostensibly it was more about the data for her.
It took Nova a couple changes before she realized I wasn't closing or averting my eyes as she swapped bras and panties.
"Sol!"
"What?"
"I said don't look while I'm changing," Nova said firmly.
"Yeah," I said.
"You've been looking the whole time, haven't you?"
I nodded. "Most definitely. I like your butt."
Nova blushed softly. "Of course you do. Not the point. I'm... not ready for you to see me naked."
"It was only from behind," I said.
"Still!"
"Sorry," I said, smirking away any gravitas my apology may have held. "Come here though," I beckoned.
Nova folded her arms across her breasts. "Don't know that I want to."
"I want to see you closer," I said. "I think this is the best bra and panties combo yet."
Nova relented a bit and took a couple steps closer. "I think so too. It's hard to find something that accents my chest without, you know, making it look like I'm trying too hard."
"Well it's working," I said. "All I want to do is get that bra off you."
"Behave," she urged, padding closer still. "What about the panties?"
"Very hot from the front," I said. "And barely there in the back, which is perfect. Spin for me?"
Nova did a slow twirl. "I can't actually dare wear them anywhere," she said softly. "They really are barely there."
"But for purposes of wanting to get them off again anyway..." I said.
"Yeah," she said, daring to crawl into bed with me. "For those kinds of purposes." She bit her lip. "You really think I look good? You're not just trying to trick me into getting naked?"
"It can be both," I murmured, pulling Nova close and nipping at her shoulder.
"Ah! No fair," she whined.
"None of it's fair," I whispered. "The things you've been doing to me lately, you think that's fair? You see me being too horny for my sis-ter and think you're getting worse research. Just consider perhaps that what you're doing is getting your brother this obsessed with you. Maybe that means it's all going better than you hoped."
Nova was quiet a worryingly long time, as I tried to distract both of us with kisses to her neck and shoulder, not quite daring for a real kiss, or to bite her any more until she said something.
"You're obsessed with me?" she finally asked.
I hesitated. That hadn't really been my point, but I had indeed said it. "Um..."
"Are you though?" Nova pressed.
"How bad is it gonna be if I say yes?" I asked.
"It would... change things," Nova said.
I sighed. "Yeah, it would, huh? I'm sorry."
I lay back. Nova followed slowly and deliberately. We lay there together, me naked, her in her underwear. Sexy underwear, even. I was still horny, but had more pressing concerns now. Such poor timing.
"I don't think you need to be sorry," Nova said.
I shrugged. "Maybe not. It's confusing."
"It is," she agreed. "But you're right. This might be counted as a pretty big success for me."
"It might well," I said.
"Are you obsessed with me, Sol?" Nova asked softly.
"I think so, yes," I said.
Nova teased fingers up and down my chest. "I might like that," she said.
"Oh?"
"I might feel kind of the same," she admitted.
"For real?" I asked, suddenly hopeful.
Nova shrugged. "It feels good making you horny. Or getting you off. Or when you really badly want to play with me."
"I really badly want to," I said, voice cracking midway through.
"I know," she said, hint of a smirk returning as she grazed my erection with her fingers. "You're pretty hor-ny, bro."
"That's what you do to me," I told her.
I tried out a quick nip of Nova's shoulder. She hissed in pleasure and curled her fingers around my cock.
"You... do things to me too," she said.
"I know. I like getting you horny," I said.
"Kinda pervy, Sol," Nova teased. "Wanting to turn your sister on like that."
I didn't bother arguing who was the more pervy, if that was the criteria we were going by. She knew very well it was essentially a tie game between us at this point.
Instead of debating, I moved in to bite her neck and shoulder, feeling the delight as she squealed and squirmed, but kept offering her tender skin up for more. My sister's body was endlessly fascinating to me as I explored her with teeth and lips, and roaming hands over her sides and tummy and thighs.
"Solll!" she whined. "That's not fair!"
"You liiike it," I teased.
"Yeah, I do. But I'm gonna need... more."
"So tell me what you want," I offered, running my fingers dangerously close to her pussy.
"I can't," she gasped. "I'd need to... take my panties off for that."
"Unf, I'm into it," I said.
"I know," she giggled. "You should have felt your cock pulse when I said that."
"So what's the problem?" I asked.
"You'd... see it," she said.
"Ideally, yeah," I said.
"That's embarrassing!" Nova said.
"It's sexy," I said. "I want to see it. I want to... do things to it."
"With your fingers?" she asked. "Maybe you could close your eyes?"
I felt the thrill run through me as my mind caught up to my own words, and I realized that no, it was not my fingers I was referring to.
"Nov," I said more calmly than I felt, "I'm not going to close my eyes. And I'm not going to finger you. Not just that, anyway. Can I take your panties off?"
Her eyes widened. "Bad!"
"I know. Can I? Please?"
Nova squirmed. "How am I supposed to say no to you right now when you ask me like that?"
"So don't say no," I suggested lightly.
She looked at me, pleading. "What if you get bored of me once you know all my secrets?"
"Are you serious right now?" I asked. "You've always been a little weirdo, but boring? Not since I've ever known you." I ran my fingers up her thigh, over her tummy. "You got your own brother looking at you this way, and you worry about being boring?"
"Well..."
"Are you bored of me now that you've seen me naked?"
Nova shook her head. "Hell no."
"So?"
"You really want to see my pussy?" she asked.
"Really, really badly right now, yeah," I said. "And... I want to try licking it."
"Unf, ok," Nova agreed. "That sounds... really nice. I haven't felt that before."
"I might not be any good at it," I cautioned.
"Oh who cares about that," Nova said. "If we're bad at it, we'll just practice more."
A weird mix of pragmatic and paranoid, my sister. But then, I understood, I thought. We were taking this experimenting pretty far at this point. Probably too far. But we didn't want to stop. If only she saw herself the way I saw her and felt what I felt, she'd know the last thing she needed to worry about was boring me.
I was more entranced and devoted with every new way that I saw her, the more exposed the better. The way she felt under my touch, the way she made me feel when she played with me. She had so much more of a hold than she apparently realized. It was more than just the physical gratification, so much more, and was leaving me so much more connected to my sister than was probably wise.
"Nov," I said softly. "Can I please take your panties off and lick your pussy?"
She whimpered and clutched part of her sheet up over her face, only leaving her shining little eyes peeking out at me. "Ok. It's still no fair asking like that though."
"How did you want me to ask?"
"I don't know. Less sexy and intense, I guess."
"But then you might have hesitated longer," I said, hooking my fingers in the sides of my little sister's panties.
"I could have thought it through better," she said. "Made a rational decision based on evidence and predicted outcomes."
I pretended to consider her point. "Nah," I decided. "Better my way."
I tugged at Nova's panties, pulling them down fast enough not to let her weasel out, but slow enough to savour the full breadth of the experience. She was still being cute and shy covering most of her face, but she was watching ever so intently too.
Her pussy drew me as soon as it was uncovered, and I barely managed to remove her panties entirely before I was lying between my sister's legs.
I was afraid of Nova getting too shy if I stared for long. I wanted to examine her more closely, but I also wanted to taste her. It was crazy how strong the urge was to lick my baby sister's pussy.
"Ah! Ooh..."
I grinned as I got immediate response from Nova. She tasted good, and I would have kept going anyway, but reactions from her made it so much hotter.
"Do you... like it?" Nova asked.
"Mmhm," I moaned in between licks.
"I wasn't sure... when I started keeping it shaved... I think boys like that?"
"Overthinking again, Nov," I said. "But... yes, it's pretty."
She made a very cute noise and shut up for a while as I ate her out.
I could tell I was only hitting a surface level of pleasure for Nova at first. It wasn't like either of us really knew what we were doing. But we both enjoyed it, and together we slowly homed in on what made my sister feel particularly good.
"Ah, yesss, suck there," she pleaded when my lips closed loosely on her clit. "Suck it. Gently!"
I happily obliged. Sucking on her felt sexy and natural to me, and the way it made her react was super fucking hot. I loved Nova's obvious moaning and squirming as she got off. I even made her cum, which I hadn't been totally sure about. I was pretty proud of myself for that one.
"Oh fuck, Sol," Nova whispered after.
"Fun, right?" I said, kissing her thigh. "See what good happens when you let your brother see your pussy?"
She giggled softly. "You're going to be unmanageable, aren't you?"
"Most likely, yes."
Nova nodded contentedly. "Good."
I crawled back up next to her. Nova appeared happy and lazy, not hardly moving even when I fiddled with her bra and took it off. She barely even put up a pretense of being shy when I finally got to check out her bare tits for the first time. Maybe I'd gotten through to her by now that I was enamoured with her, and there was no need for her to be shy about much of anything.
The biggest surprise for me was that Nova hadn't yet grabbed her notebook. It was within her reach, but instead she just kind of lay there, relaxing and luxuriating. She grinned as I played with her tits, and perhaps even arched her back a little for me, but didn't jot down any frantic notes.
"Good boy," Nova purred, patting my head as I sucked on her nipples. "Good brother."
"You'll make me hard saying stuff like that," I said.
"You're already hard," she giggled. "You think I can't feel that poking me?"
"Hehe, true."
I gently guided my sister's hand to my cock. She gripped it instinctively, and I didn't have to prod her into stroking me. She just did it like it was the only reasonable course of action once my erection was wrapped in her fingers.
There was no urgency to any of Nova's movements. She seemed quite happy to let me play with her while she jerked me off in no particular hurry. It was only when I got close to cumming that she even started encouraging me in her usual way.
"That's a good brother," she murmured. "Cum for me. Cum for your sis-ter while you suck on her tits, ok? Be a good boy."
I whimpered and came in her hand and all over her tummy while she kept stroking and milking every little bit out of me. She made it feel so good. I was helpless against her sometimes.
We snuggled together afterward. I wasn't sure which of us needed it more by then, but there was no question of me leaving for my own room.
Nova finally got around to taking her notes while leaning cozily up against me.
"Would you say you like 'good brother' or 'good boy' better?" she asked. "You reacted nicely to both of them, I thought."
"I... they're both good," I said, not bothering to obfuscate.
"Thought so," she said. "Which is good, I think, because we don't want to overdo the incest thing. Gives more options, you know?"
"Right," I agreed, somehow straight-faced while cuddling with my baby sister and lazily circling the nipple of one of her breasts with my fingers. "Wouldn't want too much incest."
"Exactly," Nova chirped, deliberately not interacting with my sarcasm. "Gotta save it for a treat."
"It always is," I admitted.
She smiled and nodded, then frowned. "You don't think you'll start losing interest now though, right? Now that I've been fully naked?"
"Again with that?" I sighed. "Nov, I don't know that I can be anything other than helplessly fascinated with you while you're naked. Especially when you're playing with me. Or vice versa."
The cheeky little smirk she gave me led me to believe she'd been fishing for something like that from me rather than being genuinely worried. This new, growing confidence in her had the potential to be dangerous going forward, but in all the best ways, hopefully.
****
I couldn't help myself but want to go to bed with my sister every subsequent night. An empty, lonely room just felt wrong in comparison.
Nova made some noises about how it was hard to keep gathering data if we didn't give any time and space for feelings to arise naturally. I'd almost think she was getting annoyed about that, except one night when I was up late watching a movie, she impatiently came to my room instead, sneaking in wearing one my shirts I must have left behind some other night. She had nothing else on, as it happened.
"You were really taking your sweet time tonight," Nova complained.
"Sorry," I said. "I was busy. Besides, didn't you want to take some nights off here and there?"
"I said no such thing," Nova said, tugging my borrowed shirt up and exposing her cute, secret little pussy.
"You did too," I said, getting naked and crawling into bed with her. "You said we're getting worse data doing this every night."
"That's true," Nova said, sighing happily as my mouth closed on her sweet little cooch. "But that's a very different statement, albeit strongly related." She bit her lip. "Yes it would be nice to see how we both felt taking a few days or weeks off, for the research of it. But I don't see how we could realistically do that now. Mmm, now that I know how good this feels." She patted my hair. "You make me feel so good."
I beamed warmly. "Excellent. I don't want to stop now, even for the sake of your notes. Maybe especially for that."
"That's ok," my sister purred enigmatically. "I have some ideas on gathering more experimental data."
I was slightly worried about what that meant, and with good reason as it turned out. It was mere days later before we had an absolutely gorgeous weekend day, no particular plans, when Nova decided to invite Skye and Aurora over to lounge in the sun.
It could have had nothing to do with me. Skye and Aurora were Nova's best friends, after all, and it would be perfectly normal for them to hang out together. Given the abnormally sexy bikinis they all wore, however, I knew what this had to be about. I didn't think any of the three of them would have dared wear anything so skimpy if there were parental figures about.
I puzzled on the matter before venturing out. Mainly as to whether I thought Aurora was in on the game. Skye had been involved already, and was no doubt still very aware of the experiments going on. Aurora most likely had been briefed to some degree, but there was no way of knowing for sure without involving myself.
There was no question of staying indoors during this. Nova had done a spectacular job ensuring my interest. All three girls wore bikini tops that showed off and flattered their chests, and left their midriffs entirely exposed. Their bottoms left them only technically modest in the front, and were nearly swallowed up from behind.
They wore outfits, I concluded, that I had never known any of the three of them to be comfortable with under any other circumstances, and were almost certainly meant get some interesting reactions out of me. I decided firmly that this must be the case, and even so it still worked like a charm. There were times when I had to admit just how uncomplicated and predictable I could be. Nova was really making it clear lately.
I debated how exactly I wanted to join the three of them outside, and ended up opting to ditch my shirt, wearing only my shorts as I ventured into the bright, sunshiny day.
Skye and Aurora were immediately shy about my presence. Not averse to it, but definitely blushy and trying to cover themselves a bit, preserve some modesty that just wasn't there. It was a mark of how familiar Nova and I were with each other now that she was perfectly at ease letting my gaze sweep over her barely covered body.
"Nice day, huh?" Nova remarked casually.
"I'd say," I answered just as calmly, not hiding the way my eyes roamed across the three girls.
"We just decided to get some sun," Nova continued airily.
As though that was all this was.
"Good thinking," I said. "Me too."
I stretched out on a lounger next to Nova, pretending to ignore her and her friends. It wasn't easy, since I really badly wanted to keep staring. I was absolutely correct that they wouldn't be content to leave things like that, though, and it wasn't long before I detected the girls up to something, even with my eyes closed and ostensibly not paying them the slightest attention.
"Hey Sol?" Nova said.
"Hm?"
"I think we perhaps forgot to put sunscreen on," my sister cheerfully informed me.
I groaned softly at the immediate implications. "Did you?"
"Yeah," Skye added softly. "We did."
I glanced over, finding Skye and Aurora both looking flustered but excited. Nova was smirking so hard I was afraid she'd injure herself due to excessive smugness.
"Your pretenses are getting awfully flimsy," I told my sister.
"Tell me you don't want to help out," Nova taunted me. "I dare you."
She twirled her pen in her fingers, notebook poised on her lap, because of course she brought it out with her. Just waiting to jot down how easily I could be made to react the way she wanted. Which, to be fair, was pretty damn easily at times.
"Not very scientific of you to always be running experiments you know the results of," I told Nova.
She frowned. "Well... damn, that's a good point actually." She sighed and looked at her notes. "My methods might be getting less scientific at that." She brightened back up pretty quickly. "On the other hand, one might think that thanks to my previous investigations and experience, I can now use my gained knowledge to achieve predictable results."
"That's a lot of words just to say you're horny and have abandoned scientific rigour, sis," I said.
Nova stuck her tongue out at me. I did the same back to her, then deliberately passed her by to go rub sunscreen on Skye first.
Skye, rolling to her front, giggled nervously as my hands touched her shoulders, then ran down her back. She relaxed into my touch pretty soon, getting used to the feel of it, and even enjoying me cautiously straddling her. I'd been half-hard already, and was quickly getting more erect as I felt up so much of her bare flesh, only lightly impeded by her scandalous bikini.
Skye gave little gasps and mewls every now and then. I felt her muscles alternately tense and relax. I let my cock grind against her butt through my shorts, and my fingers roam all over her back and down the sides of her tits. Figuring out how she reacted to every specific thing was pretty fun.