Amazingly, I started writing this as a short little humour fic about outsiders' POV on the Winchesters, and it actually stayed that way. Title taken from the incredibly awesome Community episode "Basic Human Anatomy".
Your Boyfriend's Boyfriend
Sam's day starts going downhill at recess, not that he realises it at first.
"I'm gonna do it today," he announces as he sets down his tray at the table. Annie and Bryce don't even look up from their lunches. "I'm serious this time, I'm gonna ask her out."
"Sure you are," Annie mumbles through a mouthful of tuna salad. "Just like you did last time?"
"That was different," Sam insists. "This time I'm really ready, I'm really gonna do it."
"We believe you," Bryce says. He flips a page. "But when you chicken out again and come running back, try not to look so pathetic this time, alright?"
"You guys are the worst," Sam decides. But he changed the topic anyway.
"Wait…" Alison stares at him. Sam feels his heart sink. "Why are you asking me out?"
It's not exactly the response he'd been hoping for. All things considered, it's probably better than "Ew, no," or "Great joke, Sam!" but it's still a less than stellar answer.
"Because… I think you're really funny, and smart, and pretty?" Sam asks weakly. He curses himself for sounding like a twelve year old with his first crush. Dean would be ashamed.
Alison frowns. "Don't you have a boyfriend?" she says disapprovingly. "Sorry Sam, I thought you were a really nice guy, but I don't go out with cheaters." With that, she spins on her heel and disappears into the crush of students in the hall.
Sam is left standing next to her locker, disappointment and confusion warring in his head. "What just happened?" he asks the air in bewilderment. The air doesn't reply.
"It was the weirdest thing!" he says loudly, waving his arms. The librarian gives him a harsh look and he subsides, pulling his chair closer to Annie and Bryce. "I was so smooth, I didn't stutter or anything, and she just goes," he affects a high pitched voice, "'Don't you have a boyfriend?'" He shook his head. "It was the weirdest thing," he repeats helplessly. Annie and Bryce exchange a look.
"What?" Sam demands. "Has the whole school invented some imaginary boyfriend for me?"
"Well…" Bryce hesitates. "You know how Dean always picks you up in that big black car after school?"
"Yeah..?" Sam replies slowly.
"Everyone kind of thinks he's your boyfriend," Bryce says in a rush.
Sam blinks. "… Why?" is all he could say.
"It's not that much of a leap," Annie says, rolling her eyes. "Not many seniors get driven to school unless it's by their boyfriends, Sam, and you guys hug like, all the time. And you two don't even look like each other. Like, at all," she says pointedly, as if it were the deciding point of her argument. "I mean, I thought he was your boyfriend until you mentioned that he was actually your brother. Plus, he's hot as hell," she adds wistfully. Sam's face twists.
"I never really thought about it, y'know, since he's my brother, notmy boyfriend," he replies. Bryce laughs.
"Oh, come on Sam," he says, "isn't it a little flattering? I mean, even I know Dean's pretty good looking. If the whole school thinks he's your boyfriend, they all think you could snag a hot dude!"
"It's not flattering when Alison is shouting about me cheating on my imaginary boyfriend in the hallway!" Sam almost shouts, and the librarian violently shushes him. "If everyone thinks Dean is my boyfriend, how am I supposed to get anyone to actually go out with me?" he whispers miserably.
"Sometimes life is tough, buddy," Annie says, patting his shoulder. "But at least you have a hot brother-boyfriend."
Sam's head makes a surprisingly loud thunk as it hits the table, and the librarian kicks them all when Bryce can't contain his hysterical laughter.
Knowing that every student in the parking lot thinks Dean is his boyfriend does not, surprisingly, put Sam in a good mood. It's obvious now why people would have assumed – do normal seventeen year olds hug their older brothers every day, in public? – but that doesn't mean he's any happier with it. He blows past Dean, who's leaning on the bonnet of the Impala, and wrenches the passenger door open, then folds his ever-growing legs in and slams it shut.
Dean gets in the driver's seat a few seconds later. "Dude, what crawled up your ass and died?" he grumbles, starting the engine. They peel away from the curb and are out of the parking lot before Sam speaks.
"Everyone at school thinks you're my boyfriend," he mutters. There's a pause. Sam worried for a second that maybe Dean would find this even less funny than he did. Of course, the worry is wiped away when Dean starts to laugh, loud belts of laughter until he's breathless and watery-eyed from it. Sam sulks.
"Oh, man," Dean chuckles, wiping his eyes with one hand. "How long has this been going on?"
"Apparently, since we got here!" Sam says hotly. "I only found out today because I asked a girl out, and she accused me of cheating on my boyfriend!"
Dean cracks up again, ignoring Sam's shouts of "It's not funny, Dean!"
"So now the whole's school's not only gonna think my brother is my boyfriend, but they're also gonna think I'm cheating on you!" Sam fumes. Dean fakes a pout.
"Aw, baby, am I not enough for you? Asking ladies out on the side? I thought we were forever, honey," he mocks. Sam starts hitting him on the shoulder until he finally says, "Fine, fine! What do you want me to do, make some big show when I drop you off about how brotherly and not dating we are?"
"Yes!" Sam shouts.
"Okay, okay, geez," Dean says, rolling his eyes. "Fine. When I drop you off tomorrow, I'll make sure to call you 'little brother' real loudly, that good enough?"
"We can't hug," Sam says, recalling Annie's words. "You have to… pat my shoulder, or whatever normal brothers do."
"Normal brothers? Ouch Sammy, don't knock our love," Dean replies with a grin. Sam hits him again, and Dean doesn't stop laughing until they get home.
When they drive to school the next morning, Sam taps his foot along to the ACDC blasting the whole way. Dean keeps looking over at him and grinning – maybe he thinks Sam's finally getting into classic rock. To be honest, he's just nervous about the little scene they're going to be putting on when they reach school.
Dean pulls up at the drop off zone and gets out of the car at the same time Sam does. He adjusts his backpack on his shoulders as he walks around the bonnet to Dean. Here goes nothing.
He steps up to Dean and waits for him to clasp his shoulder in the manly fashion their Dad uses all the time. Instead, before Sam can even react, Dean's grabbed his face with both hands and given him a loud, smacking kiss on the cheek, just catching the corner of his mouth. "Have a good day, baby!" he says loudly, giving Sam a sickly sweet grin. Sam can only watch in horror as Dean gets back in the car and, as he rolls away from the curve, blows a kiss to Sam and shouts "Love you!", in front of almost a third of the entire school.
He swears he can hear Dean laughing as the Impala rumbles away.
He walks through the crowd quickly, face down to hide his mad blush, ignoring every "Awwww" and "Their so sweet!" he hears. When he gets past the main clumps of students, he runs into Annie and Bryce, who just stare at him.
"Dude," Bryce says finally. Sam hangs his head lower.
"Any chance Alison didn't see that?" he asks weakly. Annie just points through the crowd to where Alison and her group of friend are glaring at him.
"I'm so screwed," he mutters. Bryce pats him on the back.
"Cheer up, Sam," he says. "At least you have a hot brother-boyfriend?"
Sam's footsteps slap on the concrete as he storms away, laughter following behind him.