Sam could fill a book with all the things brothers shouldn’t do, but which he and Dean ended up doing anyway. When he had popped his first knot he had been humping the motel bed dreaming of his big alpha brother. And it had been Dean on his mind nearly every knot since. His first rut had hit the day after Dean’s, and John had been out of town. Sam had only been seventeen—way too young to be rutting already—but just the smell of Dean in the bed next to his had been enough to pump the requisite chemicals through his blood. Sam still remembered that week with glee. That was the first time he had ever been knotted. The first time for a lot of things, actually.
Somehow, even after all these years, they were still finding new firsts.
“Hurry up,” he panted. “My turn, my turn.” He raised his ass as high as he could, clenching hard to try and squeeze the knot out of Dean faster. “Knot me,” he demanded. Dean merely grunted, well beyond words. His hands in Sam’s hair were rough. It was the third day of their rut but even though they both felt used and sore, it was impossible to ignore the demand for more and harder and mine. The stink of mating alphas was so thick Sam could taste it at the back of his throat.
Dean pushed Sam’s head into the mattress and growled, hips thrusting. The wet slap of their bodies meeting was obscene; a testament to just how much fucking they’d already achieved. Sam was so loose he could’ve fit two Deans inside him.
The thought was enough to make him writhe and moan, legs spreading even further. Dean snarled a warning and slapped him hard, holding his hip in place when this only served to make Sam wriggle more.
“Come on,” Sam goaded, voice muffled by the mattress. His heavy cock swung with every plunge of Dean’s. His balls were somehow still swollen and aching, despite the fact that he’d deposited just as much come in Dean’s ass as Dean had in his. They were both soaked in it. Dripping down their thighs and into the bedsheets. He could hear the squelch of it with every thrust.
But he still wanted more.
“Give it to me,” he demanded. “Fill me up. Wanna feel you, come on, do it, do it.”
Dean threw himself over Sam’s back and Sam stretched his head to the side so Dean’s teeth could find the bite mark. Dean latched on and Sam groaned as he felt the first telltale swell of Dean’s knot. He fucking adored every little part of his not-so-little big brother, but Dean’s knot had to be a particular favourite.
“Yes,” he hissed, squeezing hard. He clutched the sheets to stop himself from touching his dick, because as much as he loved getting himself off he loved getting off on Dean’s cock even more. “Knot me,” he chanted. “Knot me, knot me, knot me, knot m—yes!”
Ever obedient, Dean’s dick did as it was told and Sam felt the swell of pressure stretching his already stretched rim. Dean shouted around his mouthful of Sam’s flesh and he shoved, popping inside just in time for the knot to fully expand. He bit harder until Sam swore he could feel the teeth inside him and his own orgasm was ripped out of him by a feedback loop of pleasure-pain-pleasure-pain. Dean continued thrusting, jerking Sam’s hips back and forth as he did. Each additional tug on his hole forced another gush of jizz out of them both until his insides were almost as ruined as the sheets.
The scent of sated alpha drenched them both, and they panted as they came down from their respective highs. Dean eased his teeth free and licked the bite on Sam’s neck. It wasn’t a mating mark—one of them would have to be omega for that to work—but it was the only thing either of them had ever wanted. Besides, they remarked each other so often that the bite was practically permanent, anyway.
“Sammy,” Dean purred, stroking Sam’s sides, always a little bit sweet after he’d knotted. Sam didn’t like being treated like an omega, but he tolerated it if he had a dick in his ass and if that dick happened to be Dean’s.
“Mmmh,” he hummed.
They rolled onto their sides in non-verbal agreement, Sam groaning as the movement tugged at his sensitive rim. Every jostle was like a thousand tiny orgasms firing off at once. He patted his stomach tenderly, convinced he could feel Dean inside him. Dean slung an arm over his waist and grinned as Sam kept wiggling, trying to get more of the tiny-orgasms.
“Patience,” Dean crooned. He trailed fingers along Sam’s spine. “You can wait twenty minutes til your turn.”
Sam didn’t bother to laugh at that. They both knew that was a lie. He tugged a bit more forcefully than was strictly necessary and they both groaned. Dean’s knot shifted, opening Sam up slightly before his ass closed back around it, locking them tight again.
“That’s so fucking hot,” Dean groaned.
Sam turned to look over his shoulder at Dean, and raised his eyebrow.
“Oh no,” Dean said, blinking back to reality through the haze of post-orgasmic pleasure. “I know that look. Whatever you’re thinking is a bad idea.”
“All my bad ideas are good.”
Dean grumbled something about cheeky little alphas getting too big for their boots. “Okay then,” he finally said. “What?”
“Grab the headrail.”
Dean looked up and did as he was told. Sam hooked a hand under the bottom of the mattress until he could get a grip on the bed frame. “Ready?” he asked.
“Just hold on!”
Carefully, he used his hold to pull himself forward. The result was instant. The internal pressure from Dean’s knot lodged up tight against his rim from the inside. He groaned loudly, almost drowning out Dean’s yell.
“Don’t let go,” Sam begged, and then he pulled himself a little further forward.
His hole widened slightly to accommodate the bulge of Dean’s knot. Dean shouted a string of curse words and his hips flinched reflexively into Sam’s, wedging his knot back into place. Seemingly unintentionally he thrust into Sam a half dozen times, his hips jerking in short sharp jabs as though he couldn’t help himself from fucking Sam despite the fact that they were locked together and every thrust tugged Sam back and forth over the mattress an inch.
“Do that again,” Dean gasped once he’d regained control.
Sam had every intention of doing that again. He got a better grip on the bedframe and this time yanked hard, getting Dean’s knot almost to the widest point. After three days of non-stop sex his ass was well-used and loose, but opening wide enough for Dean’s knot was still more than he’d ever done. It sizzled delicious pain up his spine and from Dean’s yelp he must have almost broken a nose by throwing his head back. Sam had to reach his other hand down to stroke himself quickly, just to take the edge off, because he didn’t remember ever being this hard in his whole damn life.
“Oh my God,” Dean was babbling. “That’s the hottest thing I’ve ever seen. You’re so fucking loose, Sammy. You should see yourself right now. Do you have any idea? Do you fucking even? I can’t believe this.”
Sam eased himself back into Dean’s lap, feeling himself close back around Dean’s knot like his body was welcoming Dean home.
Oh wow, that was sappy.
But now was not the time to get sappy.
“I’m gonna do it,” he panted.
“You’re gonna do it,” Dean parroted back, sounding awed. He rubbed his nose on the back of Sam’s neck, breathing harshly. “Fuck, I love you so fucking much you know that right? What the fuck did I do to deserve you?”
Sam grinned, readjusted his grip, and began to pull.
This time, when he reached the widest point of Dean’s knot, he didn’t relax back into it. He kept pulling. He opened the tiniest fraction more and it was a combination of pain-laced pleasure that was so perfect it must have been designed specifically for him. He desperately wanted to reach back and feel himself. From the sounds Dean was making it had to be obscene back there. He wanted to feel the stretch of his hole. He wanted to feel the rigid heat of Dean’s knot while it was here: both inside and outside him.
He sank back a fraction of an inch, fucking himself just barely on the huge expanse of Dean’s knot. Dean practically sobbed, and from the telltale lush of warmth he guessed he’d squeezed a half-orgasm out of his brother even while they were still knotted.
Christ, he wasn’t far off himself. He’d never been this open in his life.
He pulled again, and his body stretched eagerly, already desperate for this new way for Dean to own him. Dean made a wrecked sound behind him and Sam couldn’t do much more than copy it, turning it into something that could be mistaken for Dean’s name. He kept tugging.
“Saaam!” Dean howled, and with an honest-to-God pop of extraordinarily orgasmic proportions his knot slipped free. Sam wrapped a frantic hand around his cock, jerking once, twice, before coming so hard he almost blacked out. His hole clenched uselessly, so fucking loose and sloppy that it didn’t have a chance in hell of closing up any time soon.
He rolled onto his other side in time to watch Dean come down from what was obviously his own rather unplanned orgasm.
“You haven’t come while still knotted in years,” Sam accused. He palmed the swollen base of Dean’s dick with his messy hand, bringing one last blurt of come out of Dean’s cock.
Dean appeared to be beyond sentences.
“Sam,” he managed. “Sammy, I. Sam. That was. Fuck.”
Sam grinned and reached back to finger himself, fitting three fingers in easily. Disgusting, he thought with an excited shiver.
Dean rolled onto his belly and tried to get his knees beneath him. “My turn,” he said, still fighting for breath.
Sam grinned and took fingers out of his own ass to shove them into Dean’s, feeling how much mess he’d already left in there. He jacked himself one-handed as he did. He could feel the flow of air cooling his insides because he still hadn’t closed up.
Oh yeah. Dean’s turn next.