fat plonk Share definition Flag When someone shits in the girl's bathroom. Specifically a black stinky one. Person 1: EW SOMEONE DID A FAT PLONK Person 2: Isabel. fat plonk by personwhowritesdefiontions October 8, 2021 0 0 Get merch Get the fat plonk mug. Buy Now — $32.95 See more merch
