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1.
Placing your bum on someones face.

Often a harmless prank among friends; usually done when the victim is laying down and unknowing. One pulls down his/her pants revealing the bare bum. The individual proceeds to place his/her bum directly on the victim's face.
"Hey, Johnny's sleeping on the couch, I'm gonna give him a bum platter."
by Ren October 24, 2004