nasty custard Share definition Flag The resulting potpourri of squishy feces after a particularly violent diarrhea episode. Dude, after the burritos and booze last night I made a really nasty custard this morning in my old lady's bed. nasty custard by Ed J. September 16, 2006 0 0 Get merch Get the nasty custard mug. Buy Now — $32.95 See more merch