Chum Chum Share definition Flag Chum Chum is extra fat/flab that is on you're forehead. This can also be related to fat layers on the foreskin. " Wow Harris that is a lot of Chum Chum you got there" Chum Chum by Tado October 12, 2009 0 0 Get merch Get the Chum Chum mug. Buy Now — $32.95 See more merch