While it's totally possible to be discrete and not break any site rules with it, I agree with Kestrel here. Go do a Google search for 'erotic roleplaying forum' and you get plenty of results for sites fully dedicated to that sort of thing and some general roleplaying forums with sections for it. It'd be easier for you to find all sorts of people interested in that realm of roleplaying on a site or section dedicated to it, after all.