Sam loves to take his time. There's usually no chance to, always on the move the next hotel, the next highway, the next hunt. Moving, moving, moving. So when he finally gets a chance to just...breathe, he lies Dean down, already stripped bare (and Dean's panting, tugging at him, 'Come on Sammy, hurry up.' So impatient, Sam murmurs teasingly into his skin, patience brother mine, I'll get there.)
And runs his hands and teeth and lips and tongue over Dean's skin, tracing old scars and new wounds until they're both shiny with sweat and spit and Dean's wordless (and he's so beautiful like that, panting and sweating and debauched, totally wreaked because of Sam. It's heady and strong and overwhelming and Sam has to take a second, panting harshly into Dean's hip and to grip himself so hard it /hurts/ because if he doesn't it'll be over too soon)
Dean strains up against Sam's arms but Sam is so much bigger than the kid he used to be, and he knows exactly how to handle Dean now. Sam coos softly into Dean's thigh, nose nudging Dean's cock and Dean's choked sound (not a whimper or a groan or a moan but something else, something primal) rolls over his skin like honey, thick and sweet and delicious. The only thing better is the sound he makes when Sam swallows him, his head bumping the back of Sam's throat.
Sam moves slowly even in this, taking his time to trace his tongue over every millimetre of Dean's cock, taking time to draw out his taste to see if it's changed since the last time he's done this (it hasn't). He keeps sucking, eyes locked on Dean, long after he comes, until Dean is whining and sobbing, pushing him away with weak hands and it's only once he speaks (begs really, 'Please Sammy please. It's too much- I can't-') that he stops.
There's no set way that they do it. Sometimes Sam will straddle Dean, sink down on him and take him so deep he can almost /taste/ it, other times Dean'll wrap his arms around Sam and hold him so close, so carefully while Sam thrusts and thrusts and thrusts. Both are good (more than good really) but now, now Sam needs to feel Dean. Needs to feel his heartbeat and his breathing (they've been through so much but they can't rest. Not yet)
So he buries himself so far inside Dean that it feels like they're one person, like they can never be apart, Dean&Sam. And Dean wraps his arms around Sam and croons in his ear panting softly ('It's ok Sammy, I got ya. It's alright, we're alright. Let go it's ok.') And Sam shatters, he buries his face in Dean's shoulder and wets Dean's skin with his tears (of fear, of relief, of joy (we're alive Dean, we're alive))
And Dean holds him as he comes down, running strong hands down his back, pressing kisses to Sam's hair and humming (it's something he's always done Mum's old lullaby, half forgotten and guarantied to calm Sam down) they fall asleep like that, curled around each other like puppies, Sam's face in Dean's shoulder and Dean's hand in his hair. And it's ok (for now at least.)