Obviously, some forums need to keep adult topics out and certainly flaming or slurs or worse have no place in adult conversation . . . but, perhaps an adult forum would be appropriate for discussion of topics that really don’t belong in the vanilla areas . . . bisexuals, threesomes, anal sex, brothels, betel nut beauties, dian tze hua che, barber shops, felching, frottage, mopery, strip clubs, snowballing, menage a taiwan, fisting, gay saunas, non-gay saunas, french kissing, rubber stamping, sexual russian roulette, porn, and a whole bunch of stuff that youngsters and some adults probably shouldn’t be learning about.
Perhaps an adult forum that requires an age in your forumosa profile for the cookie to let you in (sure, some folks can cheat but at least the forumosa folks will have made an honest effort to restrict access to appropriate folks).
Keep it moderated to keep the sex ads, porn spam, and flames out . . . but have a lose live and let live attitude towards topic content.
I don’t think a “politically incorrect” forum would be appropriate - that really is the flame forum, but even there the moderators should watch out for real abuse. Folks come here mostly to enoy the experience and share ideas not to get stomped on or abused.