McShit. Someone who uses the bogs of a fast food restaurant with no intention of eating.
If you are questioned by a manager with the assurance that you will make a purchase then this is known as a McShit with lies.
Captain Cavemans nose as a descriptor for the clitoris is my personal fave. I also have used the riposte "A confident appeal by the Australians there" when someone farts loudly too.