please help me find a kinky book

I need to find the most erotically kinky slutty book one can read. It's as a gift for a friend this Christmas so the dirtier the better. It NEEDS to be fantasy orientated or it shall go unread. Im talking, dragons, werewolves, vampires. The like. All getting it on type of deal but still following a plot. The best example I can give you is I need a book that is 90% fan service and 10% badassness.