It's not a dumb question. Ask after screening. Or after you've gotten to know each other a bit.
And also, depends on the "fetish." If you want your bottom played with, most of us don't consider male anal play anything close to a fetish.
If you want to be saved from quicksand, and then as a reward afterwards, lick the contents of a raw egg off of the kitchen floor, that might require an introduction with a bit more finesse.
So often, fetishes are so personal that it's difficult to discuss with anyone. And these desires are so deeply ingrained (don't think that I spelled that correctly!) in our psyches and can be embarrassing to share. If that is the case with you, please call me! (214-557-1017! haha)
Heck ... tell us here what you're searching for and I'm sure a bunch of ladies will chime in. I'm home and quite bored and no, not available to entertain in person today, but would adore some entertainment.
So let us know!!! (Just teasing you a little bit!)
My old "advice" used to be find someone that you like, create a bit of a dialogue, and then just ask her. Heck, worse she can do is clutch her pearls and shoo you out the door. But if you do your homework, then the right person will listen to what you're seeking and be respectful, regardless.
Good luck,
Elisabeth