Buffy: Alcohol. A sickly sweet addiction that I can't break off of. I quit only to get dragged back in. I become like an alcoholic, downing everything in sight and going on a bender and then backing off, trying to quit only to pick it up a few months later. And during these benders I have those dark spots where I sometimes can't remember what's canon and what's fanon and everything becomes a weird ass drunken haze of spander and spangel and Xander gets angsty and vamped and there's too much sex and too much bad sex and then when it's over I can't really remember exactly what I read or wrote or whatever but it all ends up okay until the next time.
Harry Potter: Crystal Meth. I feel fucking fantastic while delving. I never run out of fic and I always just feel good because I can find a really long really good fic and it's not even written well but the whole premise is just worth it. I just spend hours devouring whatever the hell I can find and I'm open to pretty much anything this side of squicky and omg I'm reading ANOTHER HP/SS fic, but who gives a crap because it's all just fucking amazing.
Firefly: Caffein. Because it's hard to find any fic and I get nervous and edgy and the fandom is closing in on itself and it feels like I'm stuck in a box. I come down from a stint of this fic and it burns because it's so sad that it's over. And you know that once you're done for the time being your done for a while and you know that once you get back into it it will only feel worse because there are even less stories and when you're done for a while you just feel sick and sad and tired.
House: Cigarettes. Easily managable but still there in the back of your brain. The medical jargon just comes over you in a wave and you let it calm you and seduce you. Sometimes you can be subdued by just the weekly show update, but every once in a while you get that ache and that need and you just reach out and snatch one story.
Supernatural: Crack. This fandom is pure crack. You start slowly, maybe pick up one story or watch one episode, but you can't stop and maybe when you start reading the wincest you're a bit squicked, but after three or four days you just get that little shiver of pleasure when you think of it. The boys are so hot and you just shake rattle and roll with the fandom. The fic comes at you from all sides and it's never bad and you can never have enough because you're just riding the wave of the ultimate high. And then maybe you can't really focus because the Dean muse or the Sam muse are there whispering badnaughtywrong things and you just want more.
Those are all my drugs. :)