I've come across them while touring the internet but never signed up to play one, except I once discovered Second Life has or had a massive underground role play for that sort of thing hidden away on some sort of island. I've also come across the occasional adult mod designed for regular MMO's.
Apologies in advance if this violates a forum rule. Just delete. Thanks.
"Change is the only constant."
"If you want to test a man's character, give him power."