really unclear if this is a popular fanon opinion but:
my general interpretation of pre-relationship wincest pining is Sam being very fucked up over the fact that he has these overarching sexual and maybe a little romantic feelings towards his brother. It’s just another terrible wrong thing that he’s unable to get over. another thing to hate himself for and another thing for dean to hate him for. as seasons go on, as with other things, he learns to live with it and understand that it’s WRONG but it was probably from the fucked up way they grew up. i think it would TORTURE s2-s5 sam (which i think is when it really kicks in) & he finds a lot of peace in accepting death whenever it comes.
as for Dean, i think it’s significantly more twisted and incest-kink ish. the fact that they are brothers is awful but it’s also kind of the thing for him. he can’t believe he’s thinking this about a guy, but at the same time, it’s his brother. where else would he place all his misguided, fucked up feelings if not on Sam? it’s always been there, he never even acknowledged when it crossed certain lines— thinking about him a little too long, when it turned sexual, when it turned violent— so in other words, it’s a little easier to ignore. or, at least, when it’s harder to ignore he can get drunk or take it out on Sam or whatever else he can fight. he hopes Sam hits back as hard. He almost never does. after their dad dies, it gets a lot worse. i think late seasons dean finds himself justified in his attraction, like “of fucking course i need him he’s my brother”. also ties into the whole sam-can’t-die & i-can’t-live-without-Sam thing he’s got going on. i think it get’s a lot less violent in later seasons or a hypothetical post-canon (where final episode never happened , of course) but s4-s10 would probably be the worst of the worst of it.
in my head in order to comply with canon i think some weird things could’ve happened end of s5 or even early or late s3 but i don’t think they’d actually both acknowledge it until lateeeee seasons. i very much believe in bottom!sam + top!dean but i also don’t think it’d be thattttt strict. they can switch if they want!
