By the looks of it there is no such a place on any booru I visited, but a lot of people out there (including me) are looking for a board where they can live out their sometimes weird fantasies.
Gelbooru is strictly against it, and e621 allows only non-sexual rp.
So, if anyone knows such a site/board where it's allowed, could you please tell me where it is?

Anyone may create an role play topic about any subject matter they like, we don't remove text unless it's abusive against a fellow viewer or spam/whining, just please clearly title it what it is and to also add: [RP] at the front.