sam's first time with a girl happens in high school and he excitedly tells dean that he slept with a girl and dean makes him tell him the whole story, except he makes sam get more and more detailed, asking questions like how did it feel and did you come? and show me how she touched you, where and then he's asking sam what he likes, and sam is getting a little uncomfortable but soldiers on, because dean always talks about his one night stands in pretty crystal clear minutiae. except for sam this isn't a one night stand, this is a girlfriend, and it's full of giddy hope and excitement.
the girl gets a little distant with sam and he doesn't know what happened, until one day he sees dean kissing her behind the school, and sam is furious, and dean coolly explains that he can't help if she liked him more. she'd break your heart, sammy, she's one of the bad girls and she's not girlfriend material. she's my kind of girl that fucks once or twice and then we never speak again. you wouldn't know because you're not experienced yet.
dean never fucks her. he gets close, undressing her in her home when her parents are out, but he keeps asking how sam touched her, he keeps asking about what sounds he made, he keeps asking how sam felt to her, and she tells dean that maybe this isn't such a good idea, and sends him away with his jeans unbuttoned and a raging hard on, after spending twenty minutes talking about how his little brother lost his virginity to her.
sam doesn't look dean in the eye for a few weeks, and dean feels dirty shame crawling up his neck, but every time he watches sam with that lanky preteen moody stride past him, he can't help but think of that girl's hands printed on sam's slim hips and smooth skin, of his wet and open mouth sucking on her tongue, and how dean can easily transpose sam's innocuous sighs and grunts into erotic moans in his head. he's going to fucking hell.
it takes a while for sam to have sex again, years even. he jerks off in the shower sometimes and tries to recall that evening he lost his virginity, but all he latches onto is later that night, lying side by side with dean in the dark, getting crossfaded as he told his older brother every single thing he thought and felt with her. and as the water starts turning tepid sam recalls dean's low voice growing huskier: did you like it? and dean's hard, hot elbow pressing against his on the motel bed, next time you should get her to suck your dick. and then he'll remember how there was no next time, and sam gets mad, and he pictures dean's eyes as he came through the door after the date, how he stared so dark and deep into sam's, and sam will come thinking of dean's hands grabbing sam's face as he told him, she isn't good for you.
