Obviously, you eventually just need to ask, but this is more about the specifics of how to go about it so that there is the highest likelihood of a good response.
There are a lot of variables in this. Are you talking about friends of yours? A fuckbuddy? Your partner? Models? I would approach each one very differently.
OscillatorSlop said: There are a lot of variables in this. Are you talking about friends of yours? A fuckbuddy? Your partner? Models? I would approach each one very differently.
Friend or partner most likely. Though that would just be me personally.
Really depends on how close or open you are to that person or participant. Rather than think of it as just a fetish, consider it from view of you asking or gaining consent from someone to be either very vulnerable with you.
If it's someone you are close with and communicate well to, honestly just being upfront with saying something like "Hey I have this thing I want to try with you, but I wanna make sure you're comfortable with"
Just be aware that as much as you are free and welcome to enjoy what you want, that you aren't entitled to someone's consent just because you really want it. So be prepared for rejection. Can't lose with asking though, so better to be honest.
Happy to give more specifics by the way, but def need more info about the other party you're wanting to initiate with and what exactly your asking to do.
Details like: how long you've known them, if you are exclusive. If you want to ask them to be in a dom/sub role. (Not fully BDsM but confirm if you are wanting to pie them, or pie you for example)
Honesty is the best policy. If you have a sexual relationship with someone, ultimately, you will try and find out one another's turn ons. Just put the kink out there, and make it very matter-of-fact. If your partner is willing, then score. I've only told my fetish to a handful of women, and while most of them merely tolerated it, this latest person is the absolute best. When I told her about it, her exact words were "sounds like fun!" And she meant it. I hope you can find partner as awesome as mine. It took me a long time.
Piederman said: Honesty is the best policy. If you have a sexual relationship with someone, ultimately, you will try and find out one another's turn ons. Just put the kink out there, and make it very matter-of-fact. If your partner is willing, then score. I've only told my fetish to a handful of women, and while most of them merely tolerated it, this latest person is the absolute best. When I told her about it, her exact words were "sounds like fun!" And she meant it. I hope you can find partner as awesome as mine. It took me a long time.
+1 to this And as Rusalka said, be prepared to handle possible rejection with some class. Good luck!
Love you, too
And as Rusalka said, be prepared to handle possible rejection with some class. Good luck! 
