Proof
He's more afraid of the consequences than anything.
The fantasies do him little harm, other than providing him with a constant reminder of what could be, had they not been raised as they were. The fantasies aren't what he was concerned about, no, because he can handle them. He goddamn loves them. It's the urges he gets sometimes, increasingly stronger and harder to ignore, like when it's the middle of the night and he just wants to kiss him, or when Sam's just woken up in the motel, hair mussed from tossing and turning, eyes half-lidded with sleep and looking utterly molestable.
The urges are a whole new level of naughty.
He wants to catch Sam off guard and kiss him, hands roaming across a body that he's seen practically his whole life but never touched, no, not like that. He wants to press their chests together, hard muscle unyielding against a somewhat softer physique. Wants to feel skin sliding on skin, breaths hot and wet against his ear, wants to touch and taste and know in a manner he's only ever dreamed of.
And the temptation is killing him.
He keeps waking up horny, more horny than he can remember being in a very long time, and every day the urges get stronger, the pull of attraction weighing so heavily on him that he's bound to snap under the pressure.
That's exactly what happens on an overcast Tuesday in November.
Sam sleeps in later than usual, sleeps soundly even as Dean tries to distract himself from the obvious wood Sam is sporting, even as Dean jacks off loudly in the shower while thinking only of rough, calloused hands and a tattoo to match his own, even as Dean trips over the blanket he'd left on the floor and lands hard, towel snagging on the corner of his bed and leaving him naked as fuck, ass up in the air.
Dean'd be damned if that didn't give him a few ideas.
He collects himself, runs a hand through his damp hair, and contemplates. He's concerned about the consequences, the things that would happen if Sam denied him, if Sam said no, if he freaked Sam the fuck out because he was propositioning his little brother, which is eight kinds of fucked up, and counting. He contemplates hard, staring intensely at his brother's crotch, and is just about to stand up and get dressed when his body betrays him.
It's an awkward lunge, limbs clunky as he hops onto Sam in one move, leaving all the gracefulness he may have had behind him on the floor. Sam lets out a grunt of surprise, but that's as far as he gets because Dean is kissing him, eyes screwed shut and lips insistent, hands balled up tight and resting on Sam's chest.
There are a few seconds of limbo, where nothing happens and the room is silent and Dean is both relaxed and terrified, and then everything shatters.
Sam doesn't know how to react, so he pushes his brother, his very naked brother, off of him, wiping at his mouth in utter disbelief. Dean is mortified, staring at Sam like a deer caught in the headlights. There is an obvious erection lurking between his legs, which would be astounding if it hadn't been /Dean/, and suddenly the older Winchester is babbling nonsense about how he slipped and lost his towel and he'd been thinking about women and a bunch of other lies that Sam can spot a mile away, and it's cute. It's unbelievably cute.
Dean keeps babbling, a crimson blush creeping steadily over his cheeks, and it causes Sam to smile, leaning forward, gripping Dean's head between large hands, and pulling him into a near bruising kiss, all sharp angles and violent pressure and shut the fuck up. And Dean listens. He falls silent, kissing back just as hard, arms wrapping tight around Sam's shoulders and pulling him closer.
Dean can't make Sam lose his clothes fast enough, seams tearing and buttons popping every which way, boxers twisted so badly over Sam's left foot that it feels like a cast. But Dean doesn't care - he's been waiting for this for years, been wanting to touch and lick and caress Sam for so long it felt like it had been forever. His fingertips slip over scarred skin, tracing along wounds that could have easily taken his brother away, and the one that did. He presses gently against that scar, lips dragging up Sam's jaw to his ear.
"This is proof of how much I need you."
The confession sends a series of rapid chills down Sam's spine, minute convulsions that Dean can feel ripple across his fingers, and he presses back, pushing his entire body against Sam's in a way that screams more.