The Endurance Test

Lilly was getting ready for bed, stripping down to her underwear bottoms. If her brother were there, she might've bothered with a t-shirt, but tonight she had the room to herself. Brian was in the next room over, spending the night with Emily; Lilly could hear plenty of it through the thin apartment wall in between, whether or not she wanted to. She had her earplugs handy in case she needed them.

Beth knocked and came in. "Hope I'm not interrupting. Can I spend the night here?"

"Sure," Lilly said. "I won't turn away a sexile."

Beth had to sleep somewhere after all, since her bed was in the room Brian and Emily were occupying tonight.

Beth sat down on Brian's bed. Lilly was still topless but she didn't bother covering up; everyone in the house had seen each other in various states of undress plenty of times already.

"We could probably split up the other boys if you want," Beth said, motioning to the third bedroom of the apartment, where Mika and Tyler were probably playing video games. "Or heck, you and I could mess around."

"No thanks. Not tonight," Lilly said. "I've got work early tomorrow. Those Christmas presents don't wrap themselves. But hey, if you want to sleep with one of the guys, go right ahead. Have them both, if you want. I won't feel left out."

The two girls sat together in silence. Well, not complete silence. Through one wall, they could hear Emily and Brian making out and muttering to each other. Through the other wall, they could indeed hear Mika and Tyler playing a shooter.

"I'll leave the boys to their video game," Beth said with a laugh. "I hope you don't mind the soundtrack, living here."

Lilly shrugged. "I knew what I was getting into. Like you told me from the start, radical free love. Anybody can have sex with anyone else. That's the rule."

"That was before your brother joined," Beth said. "I know you had...reservations about it."

"I did, at first. But then, once I got over myself, it made sense. He'd been hanging out here all the time anyway, spending the night with Emily. And it is a lot simpler to split a three-bedroom apartment six ways."

They heard Emily's cooing moan rise, and Brian started to rhythmically grunt. It was no secret what they were doing. As chill with it as Lilly tried to be, she found that the sound of people having sex always got her aroused. That part of her brain didn't seem to care that one of those people was her brother.

She was just starting to wonder how long this was going to go on, when Brian's grunts suddenly turned into a drawn-out groan. Emily's cries trailed off.

"Well, that was quick," Lilly said, keeping her voice low.

Beth struggled to keep her laughter quiet as well.

It wasn't long before the couple next door quieted down for the night.

---

The next night was a Friday, and the whole household was sitting around drinking together. Outside, it was a cold winter's night, the wind rattling the windows. Inside, the three-bedroom apartment was on the eleventh floor of a high-wise with thin walls. Heat rose through the building, making the apartment sweltering hot.

They were all wearing as little as possible. Lilly wore a t-shirt because her brother Brian was around, but she was starting to regret the decision as the beer warmed her up. It didn't help that she was leaning against Tyler's broad chest.

It was Lilly's turn to make a toast, and with her inhibitions a little loosened, she raised her glass and said, "To my little brother, for finishing fast last night so I could get a good night's sleep."

The room erupted with laughter, from everyone but Brian. Even Emily, her arm draped around Brian's neck, couldn't help but smirk.

Mika asked, "Oh, so the siblings finally did it?"

This made everyone laugh again, except Brian and Lilly.

"Gross," Lilly said.

"In my defense, it was my first time without a condom," Brian said. There were gasps around the room. They were all in the habit of using them.

Emily blushed. "Hey, what's the big deal anyway? I just wanted to try it out. It's not like either of us could get an infection from it. We're a closed circuit, right guys?"

"How far back are we talking? Because there was that time six months ago..." Tyler began.

"We get it Tyler. You're a slut. We all are. That's why we're all here, after all. To have a safe outlet for that," Beth said.

Beth was the leader of the group. It started with her and Tyler and Mika, renting the three-bedroom place for their poly triad. Then Lilly joined, and then Emily, and then Brian joined last. He started coming by to visit his sister, and eventually Brian was spending enough time there (mostly with Emily) to start paying rent.

Beth took a swig of her beer before she spoke again. "Actually, I was thinking, maybe we should help the guys out. So that they're better prepared for these exceptional occasions."

Beth gave Emily a stern look. Beth had tried birth control and had a bad reaction to it, so she was diligent about condom use. Beth had made it clear plenty of times that she didn't want to see that practice slipping away, and so she kept every bedroom stocked with them.

"What are you suggesting?" Tyler said.

Lilly felt him shift against her back. He was already getting excited. This made her lust flare up as well. She had been horny all day and was planning to get fucked tonight one way or another. At the same time, she was wary of where this was headed.

What Lilly didn't know was that, with the weight she put on at college, her birth control was no longer dosed correctly for her body mass. The days like this one, when she felt extraordinarily horny, just happened to fall halfway through her cycle, when she was most fertile.

"They need practice. I'm thinking we can do some time trials, to help them last longer and longer," Beth explained.

"Like...fucking? Right here?" Emily asked. Usually the coeds pared off into separate rooms.

"No, not fucking. Just getting them acclimated," Beth said. Then she added, "And it'd do the most good if each of the guys gets to try each of us. To the extent that we represent the breadth of the feminine form. What do you all think? Or we could just keep sitting around drinking, if you prefer."

"Count me in!" Mika said quickly.

"Sounds like fun to me," Emily said. She stroked Brian's arm, but he was sitting there stunned and quiet, maybe still sullen from being embarrassed in front of the group.

"I wouldn't turn down a chance like this," Tyler said, half to the room and half to Lilly in particular.

"Guys, I hate to burst your bubble, but there's one small problem with this round-robin idea," Lilly said. "Brian's my brother."

Beth turned to her. "And? Lilly, we knew that when we accepted him into the household. You know the house rules. Anyone can have sex with anyone else. We're all okay with it, if it happens. But if it helps at all, we're not talking about having intercourse here. Just contact." Then she asked Brian, "Are you in?"

"Uh...I mean...yeah," Brian stammered. "This is all for my sake, after all."

"If you two want to sit out the rounds where you're paired up, that's totally fine," Beth said.

Beth didn't wait around for anyone to change their mind. She stood up and clapped her hands. "Okay. Now guys, drop your boxers and lay down on the floor. Tyler, you here. Mika here. And Brian over here."

Each of them stood and lowered their boxers. Tyler and Mika roomed together and had done lots of other things together as well. They seemed completely un-shy about being bare in front of each other, and in front of the girls. Brian seemed a little more reluctant, but he didn't let himself get left behind.

It was evident to everyone in the room that each of the guys was tantalized by the prospect of what was about to happen. This was the most dramatic with Tyler's stiff, engorged member, dwarfing the other two, Mika's especially. The guys each took their places on the carpeted floor, lying on their backs a few feet apart.

Lilly had seen all of the guys naked of course. And sharing a room with Brian, it had been impossible to avoid it. Sometimes they had to change. Sometimes morning wood was a thing. But she'd been careful not to look. Now her brother was lying face up on the carpet alongside the two guys she'd been fucking regularly for about a year.

"Okay. Lilly, you'll start with Tyler. Emily, you take Brian. And I'll take Mika," Beth said.

The girls casually slipped out of their panties. Beth wasn't too worried either; him seeing her probably wasn't anything new.

"Pardon the blood, fellas. It's just that time," Beth said.

"So glad I never have to deal with that ever again," Emily said. She was on a higher dose of birth control, and never got her period, as she loved to brag about.

"Do you always talk like this?" Brian asked.

"Yes, they do," Mika replied quickly.

Each of the girls straddled their partner at the waist. For now, Lilly was furthest from her brother, which was reassuring. And Tyler was who she was most familiar with. She stroked his cock with her hand, feeling it not even fully erect yet.

"Hey. No cheating," Tyler gasped.

"I'm going to start with a timer for one minute. That shouldn't be too difficult," Beth said, with a wink at Brian. "Guys, if you feel like you're going to lose control, tap out and rejoin in the next round. On my mark, 3, 2, 1, go."

Emily lined herself up with Brian's cock, and sank down on it at the end of the countdown. The feeling made them both gasp with pleasure. She asked him, "Think you can handle this do-over?"

"I think so," Brian replied. It felt just as exquisite as it did the night before. But at least he wasn't try to thrust this time. They were just sitting there conjoined, her thighs splayed to either side of him, his erection nestled in her warmth. "Ask me again in a minute though."

Meanwhile, Mika said quietly to Beth, "Mm, I could get used to this!"

"Don't get too used to it," she teased. "Maybe once in a while."

Lilly had no trouble feeding Tyler's cock into her as the timer started. He wasn't completely hard to start with, but she felt him grow and firm up inside her over the course of the minute. It felt like too soon when the timer went off, and she had to pull herself up off him.

Lilly shifted down to Mika. She and Mika had hooked up on occasion, but they weren't a usual thing like she and Tyler were. Mika was short and a bit smaller than average down there, but he was generous and skilled with his hands and mouth. Not that it would matter in this context.

Lilly tried not to glance to her right, where Beth was getting into position atop Brian. This was all so surreal, and she knew she probably wouldn't be going through with it, if it weren't for the alcohol and the aching need inside her.

"Next round, two minutes," Beth said, and counted them down.

Brian had been with Beth a few times before. Beth was gorgeous, with her blonde hair, her tall runner's physique, and a face that lit up the room. In truth, Brian thought Beth was out of his league, and that she couldn't possibly be into him. So to have his cock deep inside her was an intense and unexpected delight.

"Deep breaths," she told him.

At the other end of the line, Emily had managed to get Tyler's large cock into her diminutive frame, but it wasn't easy. "Oh fuck oh fuck," she was muttering. Tyler's hands were clenched at his side, his jaw set.

Brian didn't make it to two minutes. He could feel the riot of sensation on the cusp of overwhelming him. Even pulling out might be enough to set him off, but he knew he was supposed to. He tapped the floor urgently, and Beth quickly rose off his lap.

He reached for his cock. It would only take one or two strokes to put him over the edge, he was so close.

Beth grabbed his arm, holding it back. "Don't. If you do that, you'll be rewarding yourself for it."

Brian was still catching his breath when the two minute timer went off. The urgency had abated. Somehow he'd gotten past it.

"Well that was easy," Lilly said to Mika, as she lifted herself off him.

"Easy for you, maybe," he replied with a smile.

Then Lilly had to give Emily a supporting hand to help her lift herself up far enough for Tyler to slip free. Emily took her place by Mika, with a relieved sigh. She knew she could handle Mika just fine.

Lilly knelt down by Brian. "So...did you actually want to do this?"

"I'm game if you are," he said. "I really could use the practice."

Lilly knew if she were thinking straight, this absolutely would not be happening. But she had already been revved up by her previous partners. And she thought maybe Beth was right. This didn't feel like fucking. It wasn't exactly chaste either, but maybe it was just chaste enough that it wouldn't be weird to be doing it with Brian.

"Let's be clear. We are not having sex," she said.

"No, of course not," he agreed.

"This time we're going for five minutes," Beth said.

"Five??" Lilly objected. "Can't we try two minutes again? Not all of us beat that level."

"Yes, we're doing five next. Five minutes is not long at all," Beth replied.

Lilly waited for anyone else to speak up, but it was just her. Fine, she decided.

The timer started, and Lilly pressed herself down on Brian's erection until it all disappeared into her. Her pussy twitched with pleasure that she resented.

Before long, Brian's breath hissed through his teeth.

"Doing okay?" Lilly asked. "You almost didn't even last two minutes, after all."

"No, yeah, I'm fine," Brian answered distractedly.

"Well, you better tap out if you get close," Lilly said. "Pill or no, I am absolutely not having my brother's semen in my vagina."

Brian gasped, "Not helping."

"Neither is your spasming cock," she said, now struggling to hide what he was doing to her on the inside. Her body wanted this, craved this.

"You're the one spasming," he said.

At the other end of the line, Beth was struggling to sit still, with Tyler filling her up. Her chest rose and fell, she bit her lip to try to keep her moans inside, but her intensity was only building, building, until her thigh muscles went taut. Then with a cry she couldn't contain, Beth collapsed forward onto Tyler's chest and started to shake. Tyler smiled calmly; he was clearly enjoying himself, but this wasn't the breaking point for him.

"Fuck," Brian muttered.

The sight of Beth climaxing on Tyler's cock was driving Lilly mad, but she couldn't let it go to Brian's head.

"Hey. Eyes up here," she said. "Don't look at her. Look at your stocky, overweight sister."

His eyes turned to her, taking her in from her chubby, rounded face, to her plump full breasts, to her broad belly, to the fuzz between her legs, and the place somewhere under there where they were conjoined. He had never been with someone like her before. Had never even considered it. Hadn't realized what he was missing out on. Until now.

"Not helping either," he whispered.

"Just hang on," she said, unsure if she could hang on either.

The timer beeped. Lilly knew they were down to the wire, and lifted herself off of Brian. But both of them made reluctant sighs at the feeling of pulling away, after being so close to something hot and explosive. From everyone else's non-reaction, it seemed like her having sexual contact with Brian--she still wouldn't consider it intercourse--truly wasn't a big deal to anyone else in the room.

"Let's try ten minutes," Beth said. She waited a moment for objections, and heard none.

Lilly moved back over to Tyler. This time his cock was standing at full staff, and glistening with the other girls' juices. She was inclined to lean down and give it a lick, but that would spoil the test. After Brian, she had more need inside of her than ever, even if she didn't want to admit to herself that Brian had done that to her.

Next to her, Beth got in position atop Mika, and counted down to the start. Then Lilly took Tyler into herself. She wasn't as tall as Beth, but she figured she was better able to handle Tyler because she had stronger, more elastic muscles where it counted.

"We've got this, right?" she asked him.

"We'll see," Tyler replied.

"You and I have gone half an hour before," she said.

"That was different," he said.

Meanwhile, Emily braced her hands on Brian's chest for support, and looked down into his eyes. Emily was Brian's favorite. Or had been, anyway. After Lilly, it didn't feel quite the same between them. He wondered if he felt the same to her either, after being stretched around Tyler.

"Hello again. Regardless what happens, you've already beaten your previous record," she said.

"Yeah, I...uh...think I'm kinda getting the hang of this," Brian said. "Though if we were actually, you know, all bets are off."

Lilly desperately wanted to get off, like she'd seen Beth just do on Tyler's cock. But she was used to doing more with Tyler. Feeling him thrust into her with all he had, knowing she was built to take it. Just sitting on him was definitely nice, but it wasn't enough to push her over the edge.

Beth could feel Mika tensing his muscles under her. She could tell he was struggling to contain himself. She had already gotten off, courtesy of Tyler, but she figured she wouldn't begrudge Mika his own satisfaction.

She leaned down and brought her mouth right by his ear so they could whisper to just each other.

"Don't tap out," she told him. "No one will know."

He didn't need to be told twice. His hips pushed involuntarily up off the floor, and as he held himself there, she felt her interior flood with his warmth. He failed to choke back a grunt, but she was too caught up in their own little world to tell if anyone had noticed.

Lilly saw Mika's scrotum contract and release, and knew that had to mean wave after wave of ejaculate between Beth's legs. Beth failed to suppress her own gasps of pleasure as it kept coming. Lilly felt a pang of jealousy that Beth was getting to have all the fun.

Brian and Emily paid no attention to anyone else until the timer went off, but then Beth got up and revealed a puddle of semen on Mika's lap. More of it slipped out of Beth's slit as she stood up.

"Oh fuck, Mika," Emily said.

Mika shrugged, with a guilty grin on his face.

"Sloppy seconds is a first for me," Brian said cheerily, as Beth knelt across his lap.

"Me too," Lilly said less enthusiastically, as she lowered herself onto Mika's cum-drenched crotch.

Emily lined herself up with Tyler, who was at his stiffest and thickest yet. She had handled it for two minutes, but she knew it'd be much longer this time.

"Fifteen minutes," Beth said, and counted down.

"I feel like a snake unhinging its jaw," Emily said, guiding Tyler into her again. She had to work to get him all the way in.

"I should be able to handle the excitement better, now that I have that out of my system," Mika assured Lilly.

She could feel him softening after having spent himself inside Beth. Lilly squeezed down on him with her vaginal floor. "Yeah, I don't think that's going to be the hard part this time."

Lilly was out of her mind with arousal, and she could already tell this wasn't going to be what did it for her either, even if her contractions to keep Mika hard kept herself excited too.

"Don't worry. You're doing great," Beth told Brian.

"Uh...thanks," Brian said. To him, it was far from a sure thing. It still wasn't. To have another beautiful woman atop him, his cock pressed into her depths, it was hard for him to ignore.

Emily was panting, as the muscles of her abdomen tried to squeeze back down to normal size, despite the Tyler-scale obstruction wedging her open. And Tyler was feeling it as well. She was tight to begin with, and then feeling her pulse and squeeze around him...Beth had already cum on his cock, and he'd managed to hold out. Mika had already broken the rules. Tyler knew that Emily liked the feeling of a man cumming inside her, she'd said so earlier. Emily was touching his every nerve ending, and eventually it was just too much. He wasn't going to make it fifteen minutes.