Bum fluff Share definition Flag The growth of hair aroung the arse area which causes such an itchyness that you end up walking like you've shit youself! If you had to be any fluff in the world bumfluff would be the shitiest!!! Bum fluff by Scottish Kaz October 20, 2003 0 0 Get merch Get the Bum fluff mug. Buy Now — $32.95 See more merch