Dean knows this isn't his fault, not really. His body's chemistry has been fucked up since the day he was born, the only Omega born to a long lineage of Alphas. He's fought that status every step of the way, overcompensating for it with a smirk and a swagger and sex with as many gorgeous women as he can find. It's always been there, ticking away in the back of his brain like a time bomb, but he'd managed to convince himself that he was just broken, that it was never gonna matter.
Twenty-one years he never had a heat. Twenty-one years, until high school was an already-fading memory and he'd successfully buried the knowledge of his status so deep that digging it back up would have been impossible. Twenty-one years, seven past when most Omegas went through a first heat, three past even the latest of bloomers.
He'd come to terms with being broken; reveled in it, even. At least it meant he'd never have to suffer the indignity of desperation, of wanting to be bent over and stuffed full of some smug Alpha's cock, of need turning the blood in his veins to molten lava.
Christ, maybe it is his fault. He should have known better, because his luck has never been so good that it doesn't run out eventually.
"Dean, please let me help you," Castiel begs him from the doorway. "There must be something I can do."
Dean curls in on himself tighter. The cotton sheets on his brother's guest room bed feel like they're rubbing his skin raw, but he clutches at his pillow and burrows deeper into the nest he's made of them anyway. He's so hot he feels like he's burning up from the inside out, but he doesn't dare throw the covers off, refuses to expose himself any more than he already has.
Castiel, the eldest of the Winchester brothers, is everything a Winchester is supposed to be. Strong. Dependable. Loyal. Alpha. Sammy, their younger brother, is also all those things. Dean likes to think he hit all the marks except that last one, but right now he doesn't care because he's so damn resentful that it's Cas who had to see him like this. Cas, who's everything Dean has looked up to his entire life, who's been everything to Dean in ways he probably (hopefully) doesn't even realize.
"Go away," he says. The words stick in his throat and make his eyes water, and he pushes his face harder into the pillow. He breathes deep the scent of cotton and their mother's favorite lemon detergent, prays it somehow makes him forget the hard length of his cock pressing into the mattress and the ball of need that coils tighter inside him every time Castiel speaks with that deep, gravel-rough voice.
"I could go out and see if I can find suppressants, surely someone –"
"S'too late for that," Dean says. If he'd had even the slightest inkling, he'd have had to start taking them at least a week ago, and you can bet your ass he would have, he doesn't even care how dangerous they are before a first heat. "Just gotta…wait it out." The last part is said on a moan, the heat coming in waves that crash over him without any warning, stealing all his breath and any semblance of dignity. The idea of going through this for any length of time is pure torture, but he has no choice.
Dean can practically feel Castiel fidgeting in the doorway, even before he opens his mouth to try again. "Perhaps I can –"
"Cas," Dean grits out, his fingers clawing in the pillow as he fights not to start humping the mattress. "Unless you're gonna find me a grade-A Alpha douche at the nearest mating club or get over here and knot me your-fucking-self, then get. Out."
The entire room goes very still. When Dean realizes what he just let slip, all the fever in his veins abruptly turns cold, and he bites down hard on his pillow to keep in all the pathetic sounds that suddenly want to escape.
"Dean?" Castiel takes a few steps into the room.
Dean shallows his breathing, but it doesn't help to make his brother's presence any less affecting. When Castiel's hand comes down to his arm, pressing tentatively to bare skin, Dean whines pitifully. He wants to move it, bury it under the blankets where it's supposed to be, but he can't move. Can barely even breathe.
"Dean," Castiel says again. "I need you to look at me."
Dean shakes his head, squeezing his eyes shut even though they're already buried in the pillow. He's been able to out-stubborn Cas practically his whole life, surely that's not a skill that will abandon him now.
"Dean." Except Castiel's tone changes. An authority he's never flaunted over Dean before rings through Dean's bones, demanding obedience. "Look at me."
He looks. He has to. Turning his head just enough to stare up into his big brother's too-blue eyes, and whatever Castiel sees in his expression makes him inhale sharply, his hand clenching on Dean's arm. Dean whimpers again, eyes sliding shut as he shudders through another wave of heat, more powerful than the rest. Castiel's touch is sparking through his body like an electric current, making him crave more, more, more, please, more!
"I'm sorry," Dean gasps when the tide of feelings begins to ebb again. He forces the words off a tongue that feels thick and dry in his mouth. "I didn't— You don't— You weren't ever supposed to know." His skin is hot with the force of his humiliation, and tears prick behind his closed eyes.
Castiel's hand seems to have a direct link to Dean's dick, because when it's no longer touching him, suddenly the desperation he's been fighting goes into overdrive, and any shame he feels abruptly ceases to matter. His cock is hard enough to drill diamond, and every muscle in his body is spasming with the need to move, to offer himself as completely as he knows how, to beg until Castiel just touches him again. Dean thinks he can hear someone moaning, but it can't be him because he's never sounded like that before, as wanton as an Omega from the romance novels their mother tries to hide, all sweet desperation for their big mysterious Alphas. He's all but sobbing as he thrusts into the mattress, trying too hard to get relief he knows he can't have.
Not like this.
But then that hand is back, hard on his waist, making Dean still. He feels himself trembling as he waits, he doesn't even know for what. When he feels the mattress shift with Castiel's weight, all the breath leaves him in a rush, and when Castiel's hand slides slowly down his thigh, still covered with his pile of blankets, he thinks he's going to come right out of his skin. "What are you doing?" he asks, his voice lower and rougher than he's ever heard it.
"Helping you," Castiel replies, and then he flings the covers off the bed entirely, eyes raking over Dean's bare form.
Dean presses his forehead against his battered pillow and lets a soft sound crawl its way out of his throat. "Cas…"
"Promise me you wanted this before the heat," Castiel says, his hand returning to caress Dean's naked thigh, making Dean shudder with yearning. "Promise me, and I'll give you what you need."
Swallowing hard, Dean turns his head again just enough to peer up at him. Castiel's eyes are dark, and his movements are more controlled than Dean thinks he has any right to be right now, an Alpha sitting this close to an Omega in the thick of their first heat. "I swear," he bites out, a truth he once promised himself he'd never reveal. "Wanted this before." He won't say how long; some secrets deserve to remain his own, and maybe his silence will mitigate just how badly this will blow up in his face later. As it stands now, though, pride has abandoned him and he can't help but beg. "Cas, I need, please –"
Castiel presses a finger to his mouth, silencing him, and Dean's eyes close as he licks at the digit, the salty taste of skin zinging through him, making him dizzy with another cresting wave of heat. He feels like he's both drowning and flying.
The mattress moves again, Castiel shifting away for a few agonizing moments, but when he returns, it's gloriously naked skin that presses all along Dean's side, soothing him. Castiel stretches out beside him, his hand trailing along Dean's spine as the sharpest edge of his desperation starts to abate. Skin-to-skin contact, and maybe he should have guessed it would have this calming effect, but no one ever told him. The air in the room stops feeling so cloying and warm, and for a second, he can breathe almost normally again. It's not enough, not nearly enough, and he knows it's going to get worse again if he doesn't get a knot in him soon, but right now, he takes the opportunity to turn into Castiel's arms and press his face into his neck and cling to him like he hasn't done since he was eight years old and broke his ankle on the playground.
"Better?" Castiel asks, his voice rumbling in his chest.
Dean nods, breathing in his brother's scent, letting it wash over him, letting it mark him the way the heat demands he be marked. Taken. Owned.
"Have you ever done this before?" Castiel's hand is at the nape of his neck now, threading through the short hair there. Dean's torn between purring like a housecat and rutting frantically against the person providing so much sweet pleasure.
"Never been fucked," he replies after a moment, trying to stop his face from flushing. The idea of Castiel inside him is enough to start bringing the heat back. Imagining being filled, feeling Castiel's cock grow hot and heavy inside him, locking them together and filling Dean with his seed, breeding him like Dean belongs to him…
"Your heart is racing," Castiel notes, brows furrowing. "Are you scared?"
Dean's flush deepens, and he shakes his head.
Castiel's chuckle vibrates against him. "Ah, I understand. Not afraid. What, then, are you imagining me doing to you, little brother?"
"Ngh," is about the best Dean can manage, and Castiel's eyes when he pulls away and tilts Dean's chin up to look at him are sparkling with warm amusement.
"Maybe we'll see if I can guess," he murmurs, and kisses Dean.
He's in heat, and every nerve-ending he has is craving every touch Castiel offers, so Dean expected their kisses, if there were any, to be fast and frantic, aching and hungry. But this is soft, slow. A seduction where no seduction is necessary. Dean moans against his mouth, and Castiel swallows the sound with a gentle caress of his tongue. Dean presses closer, and Castiel steadies him with a hand against his cheek, another around his waist. Dean lets himself fall, and Castiel catches him.
"Please, Cas, please," Dean begs, doesn't even know what he's asking for, just knows that he needs it, needs more.
Castiel lingers in the kiss for a long moment, then pulls away and deftly flips Dean onto his stomach. "Very well," he says, his hand tracing the span of Dean's back. Dean arcs into the touch, spine curving as he whines.
"Cas." He's hard as a rock again, the rush of heat returning like it never left. He gasps at the sensation of fingers along his spine, and when those fingers begin a slow descent toward his ass, he whimpers when he realizes he's wet enough to be leaking, already slick and ready and waiting for Castiel's knot.
Castiel gently presses down between Dean's shoulder-blades, and Dean acquiesces and drops down to the bed with another whine in his throat. He tilts his hips up, an invitation that has Castiel freezing in place and shuddering with desire Dean can smell now.
"We should take this slow," Castiel says, his voice strained in a way Dean doesn't think he's ever heard before. He's leaning over Dean now, breath warm at Dean's back as he presses a kiss against his skin.
"No," he says – pleads. "Dammit, Cas, please, can't take this. I can't, need you, need to –"
Castiel makes a sound that could be a groan as he shifts back, hands cupping Dean's ass, spreading it wide for the thumb he teases at Dean's entrance. Any and all words abruptly flee from Dean's brain as the heat overtakes him completely and he ruts against the pillow, fingers tearing at the sheets as he pants and groans and begs with words that don't sound like English to his feverish brain.
"Now now now now," he thinks he hears himself chanting, but it's distant and frayed at the edges and all he's really aware of is the presence at his back and the pressure at his ass and then Cas murmurs, "Dean," and slides in like he was fucking made for it, and whatever shreds were left of Dean's mental capacity short-circuit as he screams into the mattress.
Castiel buries himself deep and presses his forehead to that same space between Dean's shoulder-blades, gasping out words that Dean is soaring way too high to hear. The friction is amazing, sparking low in Dean's belly and straight up his spine and all the way down to his toes and he's never felt anything like it before, but he definitely wants to again. As often as possible. Possibly forever. Then Castiel moves, a slow slide out followed by a hard thrust back in, starting a rhythm that Dean can't even begin to match because he can't move around the intensity of it all. He manages to push back into the next thrust, and Castiel's cock hits something inside him that sends him spiraling so far into ecstasy he's sure he'll never make it back out. He screams again, muffling the sound by biting down on the mattress, and that's when Castiel cries out his name and stops dead, trembling, buried balls-deep and growing larger inside him.
Dean can feel the hard ball of that knot as it widens, spreading him so damn good he can't breathe with it, tying them together in a way that will never – can't ever – be undone completely.
"Cas," he breathes. "Jesus fucking Christ, Cas." He reaches back, desperately grabbing for his brother's hand clamped around his waist. Castiel takes his hand and squeezes tight, threading their fingers together as he gasps through the start of his orgasm. Dean can feel it filling him up, warm and wet and plugged up inside him in the best damn way. It feels like completion even though Dean's own cock is still diamond-hard and aching. "Fuck," he gasps. "Oh, fuck."
Castiel cautiously nudges forward, deeper, and inside Dean, the knot nudges right up against his prostate. He gasps again, shakes, sobs, doesn't ever want the sensation to go away but doesn't know how long he can survive it either. His knees feel like they're going to give out any moment, but when he shifts, he feels the tug of the knot, locked tight and not letting him go anytime soon, and then he can't help but cry out at how good it is, how right.
"Dean," Castiel says, rocking his hips just barely, just enough to feel it, really feel it. Castiel sounds breathless and blissed out, even more when he demands, "Dean, come for me, come for me now."
And Christ, that does it, sets Dean off like a rocket without ever being touched even once, coming all over the bed sheets in jerky, powerful spurts that leave him panting for every breath. Castiel groans as Dean clenches around him, shoving his hips again as he releases more of his seed inside him.
"How long?" Dean asks, forearms and legs shaking now with the effort of holding his weight. He presses his forehead to the mattress again as he struggles to catch his breath.
"I don't know," Castiel tells him, pressing kisses against his spine. "I've never done this before."
Dean moans, his cock giving another desperate spurt as it tries to get hard all over again. He thinks those words should make him anxious, somehow, or that he should at least be wondering about them more than he is, but like all the rest of it, all he can feel is a sense of rightness he doesn't entirely understand. And then his thoughts evaporate completely because Castiel moves, carefully holding Dean against him as he rearranges them to lie on their sides while they remain tied.
Dean sighs softly, pressing back as close to Castiel as he can get and finally relaxing now that he's allowed to, now that all the tension and need has been drained out of him for the time being. He's already half-asleep by the time Castiel's hand comes up to start carding through his sweaty hair. "We should talk about this," Castiel says.
"C'n we do that later?" Dean's words are beginning to slur. The idea of conversation is utterly exhausting when all he wants to do is stay curled up just like this and revel in these unfamiliar feelings of perfect peace.
Castiel presses another kiss into his shoulder, nuzzling the side of Dean's neck. Dean can feel his lips curving in that slow, soft smile he doesn't wear nearly often enough. "Sleep, Dean. We'll have time."
The heat satisfied for now, and feeling safer and more content than he ever has in his life while here in his brother's arms, Dean drifts off.
Castiel doesn't let go.