Of all the things to write, I feel one of the all-time toughest has got to be fetish erotica. Gay or lesbian—or straight, if you're gay or lesbian or bisexual—is comparatively a piece of cake: just insert body part of preference and go with it. For gay erotica, it's a male body, and for lesbians, it's a female body. For straights, it's the opposite. You don't have to create the ideal man or woman; in fact, it's better to describe characters that are a bit more ... real. Perfection is dull, and can be bad storytelling, but a body with its share of wrinkles, blemishes, or sags can add dimension and depth.
The same goes with motivation, the inner world of your character. I've said it before, but it bears repeating: the trick to writing beyond your own gender or orientation is in projecting your own mental landscape into the mind of your character. You may not know how gay sex, lesbian sex, or straight sex feels, but you do know what love, affection, hope, disappointment, or even just human skin feels like. Remember that, bring it to your character and your story, and you'll be able to draw a reader in.
But fetishes are tougher. To be momentarily pedantic, Webster's says that fetishes are: "an object or body part whose real or fantasized presence is psychologically necessary for sexual gratification." That's pretty accurate—or good enough for us here—but the bottom line is that fetishes are a sexual interest that may or may not directly relate to sex. Some pretty common ones are certain hair colors, body types, smells, tastes, clothing, and so forth.
We all have them to some degree. To open the field to discussion, I like breasts. But even knowing I have that fetish doesn't mean I can really explain why I like big ones. It's really weird. I mean, I can write about all kinds of things, but when I try and figure out what exactly the allure of large hooters is for me, I draw a blank. The same thing (even more so) used to happen when I tried to write about other people's fetishes.
But I have managed to learn a couple of tricks about it, in the course of my writing as well as boobie pondering (hey, there are worse ways to spend an afternoon). I've come up with two ways of approaching a fetish, at least from a literary standpoint. The first to remember that fetishes are like sex under a microscope, that part of their power is in focusing on one particular behavior or body part. Let's use legs as an example. For the die-hard leg fetishist, their sexuality is wrapped around the perfect set of limbs. For a leg man, or woman, the appeal is in that slow, careful depiction of those legs. The sex that happens after that introduction may be hot, but you can't get away with just saying he or she had a great set of gams.
Details! There has to be details—but not just any kind of detail. For people into a certain body type or style, the words themselves are important. I remember writing a leg fetish story and having it come back from the editor with a list of keywords to insert into the story, the terms his readers would respond to and demanded in their stories. Here's where research comes in: a long, slow description is one thing, but to make your fetish story work, you have to get your own list of button-pushing terminology.
The second approach is to understand that very often fetishes are removed from the normal sexual response cycle. For many people, the prep for a fetish is almost as important, if not as important, as the act itself. For latex fans—just to use an extreme example—the talcum powder and shaving before even crawling into their rubber can be just as exciting as the black stretchy stuff itself. For a fetish story, leaping into the sex isn't as important as the prep to get to it. Another example that springs to mind is a friend of mine who was an infantilist—and before you leap to your own Webster's, that means someone who likes to dress up as someone much younger. For him, the enjoyment was only partially in the costume and role-playing. A larger part of his dress-up and tea parties was in masturbating afterward: in other words, the fetish act wasn't sex; it was building a more realistic fetish fantasy for self-pleasure afterwards. Not that all of your literary experiments need to be that elaborate, but it does show that for a serious fetishist, the span of what can be considered sex can be pretty wide.
The reason to try your hand at fetish erotica I leave to you—except to say what I've said before: that writing only what you know can lead to boredom for you and your readers. Try new things, experiment, and take risks. In the case of fetishes, it can only add to your own sensitivity and imagination—both in terms of writing and storytelling, but maybe even in the bedroom.
And who could argue with that?