Family Boundaries Ch. 01

"Arguably. And you'd want her to sit on your face while you finished?"

Riker gave a little whimper and felt his orgasm stirring deep within. "Kinda, yeah."

Izzy's fingers were a practiced blur on her clit as she shifted her gaze hungrily back and forth between the porn and her twin brother.

"You notice they look a bit like us?" she asked.

"Only a very little bit," Riker said. "They've got brownish hair, sure, and blue eyes."

"And the right noses. And he looks like he could be a runner."

"I don't know about that."

"He's not the exquisitely toned specimen you are, of course," Izzy said teasingly.

"Uh huh. Well she's kinda got your ass."

"You think?"

"Yours is better, obviously."

"Yes, obviously." Izzy waited as long as she could hold the question in. "What would you do if I sat on your face?"

Riker groaned, felt his orgasm kick into overdrive at the immediate flash of imagination his sister had forced upon him, then tingled and shivered as he came over himself. Izzy liked when he came on his tummy, much like the boy in the video, and Riker happily obliged her. It only really meant a bit of a messier clean up after, and it was worth it to help Izzy cum.

Izzy felt her trigger key off of Riker cumming on himself, as it so often did. Nothing in her life had ever made her cum so consistently as watching him finish. It was to a point she wasn't even sure she could cum if he didn't. Sometimes she worried about that, but mostly it was just kind of a normal state of affairs for her.

Riker's strokes slowed down to nearly nothing as the last of his cum dribbled out onto his fingers. Izzy was still jilling fast and furious, but it wasn't long before she too gasped and shuddered, then moaned soft and low as she came.

The sibs sat next to each other, feeling the reassurance of each other's intimate presence while they calmed down a bit. Izzy then turned to Riker and carefully kissed him on the cheek, just barely missing his lips. He did the same to her.

They then each grabbed a tissue to wipe cum off of Riker, and leave him an only marginally sticky mess before bedtime.

Izzy snuggled herself nakedly under covers while Riker padded back across the floor, dropping the laptop back on their desk, and slipped into his own bed.

"Good night, Izzy."

"Sweet dreams, Ri."

****

In the bedroom next door to the twins, Zoe lay in her bed playing with her pussy. She usually couldn't hear any distinct words through the wall, but certain sounds could carry through enough to be understood. Apparently neither Riker or Izzy had yet realized their sneaky fun times weren't quite as sneaky as they thought.

Zoe hadn't realized what was happening the first time she'd caught the twins masturbating together. Some moans and whines from her sibs' room, sure, they were getting off, that was all fine and good. And then at some point she'd realized no, they weren't just getting off, they were getting off together. It seemed so obvious in retrospect. That had turned a formerly amusing thing that she overheard every now and then into something more alluring.

Zoe had considered telling Riker and Izzy she could hear them, but decided not to. She could claim she didn't want to embarrass them, but that would be a lie. It had a lot more to do with her own horniness.

The sex noises Vi and her errant trysts made were far too much, too obvious, trying to get a reaction. The twins thought no one knew what they were up to, which was sexier right off the bat. Plus, of course, brothers and sisters masturbating together was, traditionally, somewhat frowned upon. Zoe considered that a bonus when it came to eavesdropping on intimate moments.

She was something of a connoisseur of her younger sibs' habits these days. The sounds of them cumming were well known to her, as was the tradition of Riker always cumming slightly before Izzy. Zoe wasn't quite sure why that was, but all the scenarios in her head were hot, or cute, or both.

Zoe sometimes came while thinking about Riker and Izzy doing more than just masturbating together, but she'd never believed they were doing anything to that extent. She wasn't sure why, exactly, other than her long-term chronicling of the naughty noises they made at night, which arguably made her a bit of an expert.

As was her routine on the nights when the twins got up to no good, Zoe rubbed her pussy while listening to them, then eventually got off to the sounds of them subsequently cumming together. She then curled up in her bed and enjoyed drifting pleasantly off to sleep.

****

Riker and Izzy went through their classes the next day as usual. They used to get some jokes about always being together, even sharing all the same classes, but since teasing didn't usually get much of a reaction most people who knew them just sort of took it for granted these days.

They ate lunch together in the cafeteria where they were joined by Celeste and Aurora, two of their friends from the track team. The girls made a distinctive pair as they were together nearly as often as Riker and Izzy were, and Celeste's naturally red hair with Aurora's dyed blue hair made them stand out in a crowd. Rumour had it Aurora's choice of colour was a deliberate choice to go with Celeste's, though the twins had never asked and didn't know exactly why.

"Coach is making us all run laps after school," Celeste said.

"We heard," Riker said. He sat next to Izzy, now across from their friends, and holding his sister's hand under the table.

"Heard she's pissed at someone," Izzy added. "Gonna really give it to us at practice."

Aurora nodded. "We think someone mouthed off to her again."

"Oh god, really?" Izzy said. "They gotta stop doing that. We always get laps until we puke if someone's a little shit."

Riker shrugged. "I mean, running's running. It's what we were gonna do anyway."

All three girls made a face at him. "Don't know why you're so calm about it," Celeste said. "Your endurance is one of the lowest on the team."

"Always room for improvement then," Riker said cheerfully.

Aurora groaned. "Please tell me he's joking, Izzy. He's not really such ridiculous optimist, surely."

Izzy gave Riker a look. "Yeah, he's just getting a rise out of you. And succeeding."

Riker just smiled to himself and squeezed Izzy's hand gently under the table.

"Anyway," Aurora said, "we actually really wanted to ask you two about the dance coming up."

"Yeah, you guys going?" Celeste asked.

Izzy and Riker exchanged glances.

"Most likely," Izzy said.

"We don't have dates though," Riker said.

Celeste and Aurora exchanged glances of their own.

"Well we could definitely set you both up," Aurora said.

"But you both just want to go together," Celeste said. "So it's kinda pointless."

"How would you know what we want?" Izzy asked.

"You're kidding, right?" Aurora said. "How long have we been friends?"

"A long time."

"Exactly."

The twins exchanged another glance.

"I mean, it's just easier going together," Riker said. "No worrying about dates and making good impressions and stuff."

"True," Izzy said. "Plus we're better dancers than most people, and they can't keep up."

"I'd say you two are cute," Celeste said, "but I'm worried that if you guys never date 'cause it's easier not to, you're never gonna find anyone but each other."

"This is our concern," Aurora agreed.

Izzy looked at her brother, then back to Celeste and Aurora. "Enh, we could do worse."

****

Riker regretted his optimism about track practice. Their coach was, indeed, on a tear, and intent on sweating punishment out of everyone. He still didn't even really know why.

Riker could do distance running, but was much better on short distances. After several laps, he was lagging, his lack of endurance catching up with him.

The plus side, one of the good things about being the only boy running with a dozen girls, was that he had a steady stream of tight butts passing him that he could happily stare at for a bit before they got too far ahead of him.

"You'd probably run faster if you'd stop checking everyone out as they go by," Izzy said, catching up to him again.

Riker tried to shrug, which was hard to do effectively while running. "Who needs faster? I'm struggling as is."

"No denial that you were watching everyone's butt?"

"Would denying it work?"

"No."

"Then I won't bother."

Izzy snorted, an effect also marred while running and softly panting. "Trying to decide who you want to ask to the dance?"

"Based on cuteness of butt? I guess there's worse criteria." Riker shook his head. "But no, we're going together, right?"

Izzy smiled, feeling that warmth that Riker created in her that she really didn't always understand, but enjoyed when she felt it. "Of course. Just checking. It'd be harsh getting stood up by my brother."

"Yeah, right."

Izzy sped up a little and stayed in front of Riker for a bit. She waited for the curve of the running track to let her look back at him without being too obvious about it. Riker was pretty zoned out and not paying attention, but his eyes were locked loosely on her backside. She smiled to herself and kept pace in front of him until their coach finally blew her whistle and called the team all in.

Riker flopped over on the grass, unashamedly sprawling out and pretending to die from exertion. The performance got a few giggles.

"Very funny, Mr. MacIsaac," Coach Watson said, rolling her eyes at the theatrics. "You know it just makes me think we need to work on your distance running more."

"I'm built for sprints!" Riker protested.

"You're built for whatever lets you sit your ass back down again the soonest."

"Same thing."

Coach Watson pursed her lips, but couldn't help a small smile at Riker's antics. "You're just lucky you're the entire boys' team by yourself. You'd be in trouble if I had options."

"Funny," Izzy said, "that's what I always tell him too."

Riker stuck his tongue out at his sister, still flat on his back on the ground.

Coach Watson shook her head, then looked down at her clipboard. "Anyway, I got word that recruiters will indeed be at the next meet, as we'd hoped. They--"

Izzy groaned. "Is that why you were punishing us today?"

"I wasn't--"

"Yeah, we thought you were pissed at someone," Aurora said.

"I'm really not so petty as that," Coach Watson said, eyes narrowed. "You lot do your best to shirk endurance training at every opportunity, but you need it sometime."

"Oh," Celeste said. "Well... I guess that's kinda true."

Riker raised his hand. "I don't."

"You especially do," Coach Watson said.

"No, see, I'm comfortable with my weaknesses and want to learn to love myself as I am. If I--"

"Two more laps, Mr. MacIsaac."

Riker got to his feet with a long, dramatic sigh. "This is sexist, you know."

"No, this is you being a show off and suffering the consequences."

"She's got you there, Ri," Izzy called cheerfully at her brother as he jogged back onto the running track.

Izzy noted, as she often did, how many eyes fixed to Riker as he retreated. She'd wondered if he ever noticed how many of the girls checked him out from time to time, or if he was too busy checking them out to notice. She felt a small surge of protective jealousy at all the attention on him, along with happiness for her twin brother that he could command such interest. It was a difficult pairing of emotions at times. Confusing, if nothing else.

****

Riker got a whole shower room to himself after practice. Sometimes there were other sports happening at a similar time so there'd be more boys around, or sometimes if it was in the middle of the school day there would be plenty of regular use. A fair amount of the time it was just him. One of the perks of being the only boy on the track team.

That and being surrounded by hot girls. That didn't hurt either. It made running difficult at times, sure, and was probably just as much to blame for his poor performances at times as were any of his actual faults. He couldn't really help his cock getting in the way.

It currently throbbed gently under the spray of water as Riker rinsed off the sweat of the practice. He really did enjoy running with so many hot girls, though he would have done it just because Izzy liked it. And not just because he preferred watching her butt the most out of all of them.

"I really thought you'd be jerking off," Izzy said.

Riker turned and saw his sister padding toward him. He tilted his head curiously.

"What, did you sneak in here just to catch me at it?" he asked.

Izzy had, in fact, done precisely that. She'd slipped away with her stuff to the boys' locker room, which she was delighted to find was empty other than her brother. She'd hesitated momentarily and just watched him wash himself off, then gone ahead and taken her running clothes off so she could shower too. Choosing the showerhead next to Riker, the twins each stood nude under the spray, eyeing each other and gauging the other's mood.

"It was too crowded in the other shower," Izzy lied smoothly.

"Sure it was," Riker said, not buying it for a second. "It so happened to be too crowded the very day after I told you that I sometimes jerk off in here by myself?"

"... yes."

"Quite a coincidence."

"Not enough of one. You aren't even jerking off."

Riker's eyes flicked down to his erection, currently pointed directly at Izzy, then back up to her. "You know, you could just ask."

Izzy rolled her eyes. "Oh I see. Turning my own words from last night back against me, huh?"

"It's only fair. We can both ask for stuff if we want it."

"Well what do you want right now? Maybe I don't want to force you into jerking off if you don't want to."

Riker considered the question. It was, admittedly, very difficult to think straight with Izzy so very naked and wet in front of him. He was used to being naked with her in the safety and comfort of their room, often in the dark. This was quite different.

"I think, maybe, that mostly I want to jerk off when you want me to," Riker said eventually.

Izzy had her turn to think seriously, which was just as tricky for her standing next to her wet, naked, very erect brother as it had been for him. "Because it's hotter that way?"

"Maybe. More because... it feels right. Like... like everything feels better if I know you're enjoying yourself too."

Izzy cocked her head. "I get that. You know I struggle to even cum if I don't see you cum first?"

"I'd kind of wondered about that. What about, like, when you have your dates with Mr. Showerhead?"

Izzy blushed faintly. "Well... it's nice, but it's harder to cum. And I usually have to think about you cumming. A lot of the time I just don't even get there."

"Oh."

"What about you?"

"Same, kinda."

"Like you stand in here and think about me?"

"... yeah."

"And here I thought it was all those butts you were checking out while we were running," Izzy teased.

"It is. That's what gets me going. And then... and then it's always just one after a while."

Izzy bit her lip and stared at her twin brother with big, hopeful eyes. "Mine?"

"Yours."

Slowly, carefully, Izzy turned around so her back was to Riker. "And like, what if I did this?"

Riker's eyes traveled down the smooth curve of his sister's back to her tight, wet ass. "That might get me," he admitted, his voice cracking a bit.

Izzy looked back over her shoulder. "Not enough, apparently."

"Maybe... maybe bend over some?"

Izzy's heart pounded. She tried to act casual as she kept her legs slightly spread, knees straight, and slowly leaned over until she was at nearly ninety degrees. It was by far the lewdest pose she'd ever struck for anyone, let alone her brother. She again looked over her shoulder while bracing her hands on her thighs.

Riker whimpered softly as Izzy bent over. He kind of couldn't believe that he'd gone ahead and asked her to do it. Seeing her in that kind of pose was a far cry from just masturbating together in their room like normal. He saw her head turn just as he was grabbing his cock, and watched the question she was about to ask die on her lips.

"So that's what it takes, huh?" Izzy said, watching Riker's hand move on his shaft with a fixed, unblinking gaze.

"Sometimes, I guess."

"What do you do when you don't have a sister around willing to pose like a porn star?"

"It's a struggle."

"Uh huh."

Riker stroked himself faster, so crazy turned on beyond what he usually felt while showering after a practice.

Izzy found it hard to keep still for him as she got all buzzed up too, her heart still hammering and her legs getting a bit wobbly.

"You aren't going to rub yourself too?" Riker asked.

Izzy started slightly at the question. "What, here? What kind of girl do think I am?"

"... is that a serious question right now?"

"Just... shush and just cum already."

"I'm going as fast as I can, jeez."

Riker reached out without thinking and put his free hand on Izzy's ass cheek, gently spreading her butt for an even more intimate view. She gasped but didn't protest. Riker was fixated on his twin sister's ass, and to a lesser extent her pussy, but the lewdness of it all still only worked for him so intensely because it was all part of Izzy, and he knew it.

Izzy trembled at feeling her brother's hand on her butt. She had a flash of disbelief at how readily she'd shown herself off to him like this, and how easily she accepted him spreading her booty even more. That was followed by the easy acceptance that yes of course she'd do this for him. She would have done it long ago if he'd ever asked. But then, neither of them would have asked for anything like this. They were twins first and foremost. Always would be.

And yet... here they were. Izzy had gone over and over the idea of sneaking in here with him, considered the dangers of getting caught at it, recognized how stupidly horny it was, and she'd still done it. After that, it had seemed way less crazy that it usually would have to just present herself like this and watch him jerk off to her.

"It's, shit, it's hard to finish," Riker said.

"Even grabbing my bum like that?"

Riker's hand jerked away, to Izzy's inner disappointment.

"Sorry."

"No, it's--"

"Usually when we do this, it's when you're gonna get off too."

Izzy trembled, feeling like she should probably stand up straight again, but refusing to do so. "So... so you cum when you think I'm going to, and I cum when you have?"

"It's kinda how it usually is, isn't it?"

"... did we get ourselves stuck in cumming paradox?"

"Not quite. But yeah, basically."

"Shit." Izzy took a deep breath. "Ok, don't think I'm gonna do this all the time, 'cause I'm not."

"What are--"

"You need to cum on my ass, Ri."

"Iz...."

"Like right now. Cum on it."

"Oh my god."

"Look, I know this is different from just masturbating together. Maybe I shouldn't have come in here like this. I was horny. It happens. Maybe we should just stick with getting off together before bed like normal. That works for us. It's just twin stuff."

"I don't know if that's normal twi--"

"But Ri, if you don't cum on my ass right this fucking minute, I'ma kick your ass."

Riker couldn't figure out exactly what was happening. It was something very close to dirty talk, but not quite. Whatever the hell it was, it worked.

He honestly didn't know if it was Izzy's demand that did it, as though his body would naturally just obey her, or if it was her constant reference to cumming on her ass. The latter seemed the more likely. Riker had been wondering before that what would happen if he came on her. One of those horny thoughts. He probably wouldn't have actually done it. Probably. But if she was insisting firmly that he had to, well that was a different story.