Based on Season 3, Episode 5 "Bedtime Stories"

Prompt: "I am the oldest and I'm doing what's best – you're gonna let this go, you understand me?" – Dean

Sam sat there in silence: the words Dean had chosen were a direct echo from some years before. They were words Sam struggled with even then; they were words he'd never had the chance to dispute.

It had been pre-Stanford. They were stuck in a motel room over winter under the siege of snow and the threat of the demon their father was out hunting.

Time led to boredom and boredom led to plain stir crazy. Sam, having long since finished his winter reading list, had started on his summer one.

He had spent the holiday stretched out on his bed, leaning on his elbows, his head in a book; while around him Dean cleaned his guns, flicked through Dad's journal and watched bad porn on the TV. Even the latter didn't get Sam's attention. It was only when Dean waved a freshly opened bottle of Jack Daniels in Sam's face that he finally got his brother's attention.

"Thought that book was more interesting than me for a second there"

"It is"

Dean looked disgruntled but didn't ask him what the book was about; if Sam wanted to tell him then he would. Sam changed the subject.

"You gonna pour me a glass then?" He asked, tossing his most recent project to the side where it fell off the bed and onto the floor.

"What? And get my baby brother drunk?" Dean feigned repulsion then laughed, "You bet your arse I am" He tipped the whiskey into two of the cups the motel had provided in the bathroom then, dragging a chair over, came to keep Sam company by his bed. Dean's glass was slightly fuller than Sam's – just to prove who was in charge.

As they laughed their way through half the bottle they talked about past monsters and past monstrous dates with various never-last-long girlfriends. They carefully skirted around the subject of their parents.

Dean sipped his drink – now sitting with his chair turned round, legs either side of the back rest, head leaning on the top – and watched Sam. He liked it when Sam got drunk for two reasons.

The first being that Sam was a happy drunk – all his worried left him and he inevitably ended up in a pool of giggles on the floor. The second reason was that he knew Sam didn't get drunk with anyone else. Like so many things about Sam, Dean was the only one to know him like this: half of Sam was a secret to the world, and the world to his big brother.

As Dean watched, Sam collapsed into a fit of laughter and promptly fell off of his bed. Dean carefully untangled himself from the chair and went to see to the glass that had fallen from Sam's hands. He placed it next to his on the night stand.

"Good thing it was empty Sammy – it's bad enough wasting whiskey on you, never mind the floor."

Sam tried to laugh again but his head was spinning and somehow he seemed to have got it tangled up in those great limbs of his. Dean sighed and reached down to pick him up.

"God you got heavy," Dean complained, reaching under Sam's arms and lifting him onto the bed. Sam slipped on the edge of the mattress and they both went sprawling over onto the duvet; Dean landing on top of Sam.

"You're not exactly a light weight yourself," Sam grumbled, trying to break free, but in his alcohol addled state just pulled Dean closer; the warm body pressing against his causing him to instinctively buckle up towards his big brother.

Dean froze and Sam froze with him – sure they'd wound up pressed against each other in more life threatening situations than this, when space was of the essence, but never crotch to crotch.

Slowly, ever so slowly, they began to move back towards each other.

"What are we doing?" Sam asked, looking straight into Dean's eyes.

"I have no idea," Dean murmured back, pressing his erection further down onto Sam. He had never been so hard in his life and they hadn't even kissed yet.

Yet. Now he wanted to, wanted to so bad his lips were aching with it, but he looked down at Sam and knew he should stop whatever this was before it got any further. And throw out the whiskey. Bad whiskey.

But then Sam took the decision away from him, pressing his lips hungrily up towards Dean's and gathering the other's mouth in his: wet and demanding. Dean sat up, pulling Sam with him so as never to break the contact. He settled himself further into his little brother's lap, wrapping his legs around Sam's back so there was no space between them, save the moment when Sam began to pull the shirt from Dean's torso.

Pausing the kiss momentarily, Dean mimicked the movements with Sam's top and then began biting into Sam's shoulders; biting and licking and leaving hickies that would stain for a month. Sam tossed his head back feeling the sweat slide down between his shoulder blades and began to fiddle with Dean's belt, before giving up and throwing Dean over so he was under him; Sam then leaving trails of kisses down Dean's chest, over his nipples and down to his belly.

What happened over the next two hours was predictable and pretty miraculous considering that really they should have been far too wasted to even get it up.

In the dim light of the winter morning, Sam snuggled into Dean, a very sweaty, naked version of Dean, and was severely irritated when Dean shoved him off and exited the bed.

"Dean?"

"Shut up Sammy"

"Why? You think I don't remember what happened, that I didn't want it?" He tried to pull Dean back into the bed, but stopped when he realised that there was a solitary tear trickling down his brother's face.

"You don't know what you're saying Sammy."

"I do, Dean. Look at me – I do"

Dean spun and looked down at his little brother, tangled in blankets stained with them, and dropped a gentle kiss on his forehead.

"No you don't Sammy, which is why I'm making the decision for you - I am the oldest and I'm doing what's best. You're gonna let this go, you understand me?"

And with that he vacated the room for a shower and left Sam with thoughts that would haunt him every day for the rest of his life.