Sam can never quite pinpoint the moment that the decision is made. It could be when Dean makes a passing comment that isn't quite what one would call brotherly, or when it's quiet and nothing's being said and there's only the steadily thickening air between them – or maybe it's made when the innocent, smiling hotel receptionist asks "just the one bed?" and they share a look and they know exactly what she's saying but for some reason if it comes out of either of their mouths it's a sudden profanity, and they act offended. No, we're brothers, what are you implying?
Brothers. Just a word. You can spit it out along with the blood. Easy as that.
Either way, Sam assumes it must be days like these when the space between them feels too much and when Dean's eyes linger for just a little too long and when they don't even make it to the bed at first, one pushing the other roughly against the wall as their lips meet and their hands wander with both aimless bliss and heated purpose.
It's difficult for Sam to keep himself in check when Dean's like this, all hands and hips and gentle pulls on Sam's lower lip with his teeth. He can never quite decide whether to pretend he isn't desperate to push Dean over to the bed and shove him into the mattress like it doesn't mean a thing, or to just let himself tighten his arms around Dean and gasp into his mouth as their hips move together and continue just to tempt until one or the other gets too desperate and hands wander far enough down to confirm the outcome of the situation.
As Dean's lips move to his neck and his teeth drag a little against his burning skin, Sam decides that today the sheets are unfortunately going to have to be ruined, and later on they'll just have to buck up and get over it.
He pulls Dean closer at the waist and shoves his hips against the other man's, shivering a little when he feels Dean's warmth and hardness through his jeans against his own. Taking advantage of Dean's temporary surprise, he forces him over to the bed and pushes him down into the sheets, moving his leg so that it aligns with Dean's thigh and pulling him up by his shirt to kiss him fiercely, his free hand running through Dean's hair. He pushes Dean's shirt up past his stomach impatiently, quickly becoming desperate for the feeling of skin on skin, and as Dean quickly pulls his shirt over his head he busies himself with undoing his own belt, swiftly pulling it out of its loops and tossing it aside along with Dean's shirt. He pushes Dean down by his shoulders and pins him down at the hips, grinding against him just to hear that sharp intake of breath and see those perfect lips twitch a little at the corners. He slides his hands down Dean's torso and stops at his fly, unbuttoning it with clumsy but determined hands and practically tearing the zipper down. As he's about to pull down his jeans, Dean grabs him by the collar of his shirt and pulls him down, then rolls them both over so that Sam's underneath him. The swiftness of it is both surprises and arouses Sam, and he gasps a little when Dean's hand slips underneath his pants and slides against his cock through his underwear, his other hand unbuttoning Sam's shirt quickly and easily. He bucks his hips into Dean and allows himself to forget for a minute that he's meant to be fighting for dominance, lets his back arch a little into the rhythm of Dean's palm. But it's not completely overwhelming and he can gain enough control to shove Dean's pants down to his knees, and his hands are moving swiftly toward the waistband of his underwear when Dean grabs both of his wrists and pins them down on the bed. Sam feels his breath leave him in a quick huff as Dean pushes into him, a grin tugging at the edges of his full lips.
"I win," he smirks, pushing his jeans down fairly efficiently using his knees and feet. Despite his irritation at Dean actually thinking he's got Sam pinned, he can respect that holy crap, this guy can get his clothes off quickly. He shifts a little up the bed as Dean tightens his grip on his wrists and leans down to kiss his neck, his teeth scraping a little, his tongue warm and quick against Sam's bare skin. Sam is extremely aware of Dean's hard-on pushing into him, and his pants are feeling far too tight, so he quickly pulls one hand from Dean's grip and tries to push his jeans down – but suddenly Dean has him at the wrist again, and this time he really has him, and he's so close he could count every freckle across the bridge of his nose and scattered across his cheeks.
"Nope," he said firmly, shoving his hips into Sam's so he gasps a little. "Winner decides when the clothes come off."
"Who says" – Sam grunts, locking his legs around Dean's hips and pushing his arms forward so that he rolls over and lands on top of Dean – "you're the winner?"
Before Dean can stop him, he pushes his jeans down with one hand and pulls them off his legs, throwing them aside and catching Dean's hand as it reaches for his shoulder. He's determined to win this, and he's not sure when it became a competition but all he knows now is that he has to win. He pulls Dean up into a sitting position and kisses him hard, hands moving to his hair and neck, keeping him there. He shifts against Dean, feeling the weight of Dean's cock hard and heavy against his and suddenly he just needs him, needs to have him here with his hands making fists in the sheets and his back arched and their breath coming in trembling gasps and their skin burning and aching to be touched all over. He shoves him roughly into the bedding again and rolls his hips into him, arching his back so he can leave a trail of kisses along Dean's neck and jaw. He knows he won't win, and he knows that in the end it won't matter, and they'll still be clinging onto each other with all the force they can. But for now, before it turns into that familiar sheet-gripping, sweaty-palmed bliss, it's better to pretend that they're still fighting, one over the other, tooth and nail and everything they're used to, everything they've been training for. That's how it always was, and that's how it always will be.
After all, what's the point of changing something that's already perfect as it is?