poo sap Share definition Flag The last part of a beer, comprised mainly of flat beer and grose fizz. Smells like shit. Prominent in beer pong... "Shit mayne! Rest of this cup tastes like poo sap!" poo sap by Shwandito Filiwyperson January 14, 2008 0 0 Get merch Get the poo sap mug. Buy Now — $32.95 See more merch