I really, fundamentally don't get fic or pairings where one partner is defined as being always the top, or always the bottom. [Disclaimer: this does not mean that I have not read and adored particular fics of this type, only that I had to overcome my issues to like them.] I guess you could call this a squick, of a sort, except that it's not a knee-jerk EWW reaction, so much as a pervasive sense of discomfort.
I don't believe that sexual positions necessarily echo power in a relationship. I just don't. I think that someone can absolutely love getting fucked, and still be loud, forceful, and masculine. Hell, there are certainly women who wear the pants in their heterosexual relationship who don't want to peg their boyfriends. It's penetration, not a set of handcuffs. I also don't really understand the idea of a slash couple that never switches. Even if there are preferences, I still would think that sometimes, you feel like taking a walk on the other side of the fence. They can both feel good, right? And from time to time, I'd think everyone is in the mood to get fucked, regardless of what they usually prefer, or what their genitalia are.
It also bothers me on a political level, a bit; the whole butch/femme dynamic is so very heteronormative, mapping a traditional heterosexual power relationship onto a queer couple. I can absolutely get that you might skew towards one gender paradigm - I myself very much like wearing pretty dresses and heels and earrings - but I really don't understand how you couldn't sometimes feel like putting on dirty jeans and moving furniture or something. SOMETIMES, you know? And I guess the real crucial thing here, the key to my discontent, is that if you *are* entirely 100% all the time a submissive feminized bottom, then I think that's got to at least partially be a choice and a kink, something you're doing deliberately because it gets your rocks off to play that game.
And that particular game is not all that interesting to me. Because that isn't my kink. I'm also not particularly into D/s relationships in fic. This might be because for me to believe that, I really do have to be walking out onto a ledge of fantasy, a ledge where yeah, some real people choose to live their lives - but it's THEIR fantasy, not mine.
I guess what really squicks me is when characterization *is* the fantasy, instead of supporting a story about two real people *playing* with fantasy, or thrust into a fantasy situation By Means Of Plot. (Hi, aliens who made them do it!) Second Skin is the latter type; I have no particular interest in crossdressing, but I sure as hell want to read about JOHN being insanely turned on by crossdressing. Whereas a lot of badfic, and even a lot of well-done hardcore BDSM stuff, is really the AUTHOR'S fantasy. It has nothing to do with the characters really, they're just actors putting on a sexy show for the author and the readers both. Which I'm only sometimes on board for, and only when it happens to be my kink, and only, only in the shallowest of ways. They can be, um, useful? But when I'm done, I have no real interest in the story beyond that. It's porn in the men's-magazine sense.
As you might expect, I also have issues with Yaoi. (Some Yaoi fic is excellent, of course; my issues are with the Yaoi establishment, such as it is.) Seme/uke? PLEASE. That, to me, has no relationship to the real world at all, and real people are what I find sexy. Even if all gay couples did comprise a tall, dark-haired, serious, older guy and a blond, mischievous, short younger guy (who likes ramen), I still wouldn't want to read endless stories about them, because OMG boring. The fact that the notation of Yaoi pairings revolves around who gets fucked by whom revolts me. It's all the fucked-upness of patriarchy, without even including a female character! AWESOME.
Oh, oh, here's my point, maybe: if you force your characters into a classic D/s, top/bottom relationship, then you will appeal to other people who enjoy fantasizing about that kind of relationship. But if you write a fic in which *your characters*, your real-world, recognizable characters, enjoy fantasizing about, and playing with, that dynamic, then you might well appeal to people who don't share your kink. Or, hell, don't make it a big deal at all who fucks who. But don't expect me to believe that greedy-little-slutty-bottoms are not someone's kink - and if your fic is going to impress me, than it's probably the character's, rather than the author's.
Lolita is sort of the same thing, on some level, maybe. Little girls are not Nabokov's thing, and as a general rule, they're not the reader's thing. They're Humbert Humbert's thing. And yet Nabokov does such a good job of conveying that lust that I actually had to put the book down midway through, because I was so uncomfortable with the way it made me feel, the degree to which I was identifying with Humbert's desires. That's a compliment.
[A final disclaimer: if you're on my flist, then you're there because I love your writing and/or you yourself, and this essay is not talking about you. Even if you're not on my flist, it's a pretty sure bet this essay is not talking about you. Mostly, this essay is talking about me.]