if u want to do manually directory submission - then go to http://www.search4i.com/Society-Culture/Adult
there are not many quality adult directories that accept free submissions. some submitters run their own directory networks which pretty muc run on the same IP or 2 without any or low PR which dont really add much value. i'm considerind adding couple of adult link building serviecs on my site in the future but for now, if you have a quality site then feel free to submit it to my adult directory