Green’s Dictionary of Slang

1. urination [= piss n. (2)].

1998

R. Puxley Fresh Rabbit.

2. a drinking spree [= piss n. (3)].

a.1945		L. Payne private coll. n.p.: Drink (—) Cousin Sis.
2003		‘Cockney Rhyming Sl.’ on Phespirit.info 🌐 Piss (On The)...................Cousin Sis.