Crust Bunny Share definition Flag Combination of dust and crusty skin that gathers and congeals inside an overweight person's navel. "You should have seen the crust bunny that I scooped out of my belly button last night!" Crust Bunny by Michael Gebhardt May 17, 2007 0 0 Get merch Get the Crust Bunny mug. Buy Now — $32.95 See more merch