Adult has fallen on some hard times lately, domain names in that space have dropped in value dramatically ( unless you have premo domains or good type in traffic)
I sold off most of my adult domain portfolio a few years back as i saw the writing on the wall. That being said if its a good name try to get it into one of monikers adult auctions or post it on a few of the adult boards for sale. Or you could contact evan @ huntingmoon.com he brokers alot of the higher end adult domains