P.I.S.S. Share definition Flag Stands for Patricia's Irish Secret Service I'm sorry but P.I.S.S. is top secret, we could tell you, but we'd have to kill you. Or at least ask you to not talk about. P.I.S.S. by Bigger P-Ness September 3, 2009 0 0 Get merch Get the P.I.S.S. mug. Buy Now — $32.95 See more merch