poo masties Share definition Flag 1, To finger ones ass while masturbating 2, To defecate in ones hand, and then use that hand to masturbate Damn, i heard that Michael loves to get into the poo masties after listening to Elton John poo masties by jigsaw666 April 8, 2008 0 0 Get merch Get the poo masties mug. Buy Now — $32.95 See more merch