bum cakes Share definition Flag A term for a large woman's anus cheeks. Used by a man who is excited by the size of them. "Talk about bum cakes, my girl's got 'em." - Spinal Tap bum cakes by Geoff L. August 30, 2005 0 0 Get merch Get the bum cakes mug. Buy Now — $32.95 See more merch