A mythical creature who flat narrow butted girls wish to for more attractive butts.
The ass fairy visits them while they sleep and with a wave of the magic wand endows them with magical man getting ass.
See Tit Fairy.
Kim Kardashian has been visited by the Ass Fairy way too many times!
A not so mythical creature who vistits you in your sleep, buggering you with out disturbing said slumbering. The ass fairy then leaves you half a roll of quaters on the night stand, a half pack of ciggerttes taped to your palm, and a sore arse.
Andy "Dude I passed out at Jeff's party last night and got visited by the ass fairy."
Aaron "Oh Ya, how do you know?"
Andy "My ass hole hurts like a mother, and a had a half-pack of marb's duct taped to my hand, but at least he gave me bus fare."