Headcanon
Headcanon1 (or head canon, head-canon) is a fan's personal, idiosyncratic interpretation of canon, such as habits of a character, the backstory of a character, or the nature of relationships between characters. The term comes from the fact that it is the canon that exists in a fan's head.
Gonna caveat this with a very loud THESE ARE MY HEADCANONS. I'M NOT TRYING TO CLAIM ANY OF IT IS CANON, and I'm especially not claiming that my ship is canon.
I don't need to claim my ship is canon. Sam and Dean are soulmates. If you feel the need to yell at me about that or any of my not-explicitly-canon headcanons, or meta, or anything, start with hitting me up @bloodwrites@fanglitch.space. It'll be fun.
On with the show...
Dean is Bisexual
I cover this in a little more detail over on Meta, but because this is my headcanon page, I can be a little more definite here. Dean checks out dudes all the fucking time, and his epic crush on Dr. Sexy just brings it all home for me.
Some fic on the theme:
Dean's totally a bottom
Dean's submissive in bed, as can be seen in almost every sex scene he has with a woman. And when it comes to wincest, Dean's definitely a bottom, because have you seen Sam in every sex scene he has with a woman?
Case closed.
Supplementary: he also likes to be held down in bed, oh yes
Some bottom!Dean fic for your enjoyment:
Dean was a sex worker
This is pure fancy on my part but it's headcanon, so that's allowed, and I like to think that if Dean had had to, he would have engaged in sex work in order to put food on the table and a roof over Sam's head while John was off hunting somewhere for weeks at a time.
Some fic in which this is the premise: