Green’s Dictionary of Slang

(drugs) phencyclidine; a marijuana cigarette mixed with phencyclidine.

2001		ONDCP Street Terms 7: Dipper — PCP.
2003		Microgram Bulletin XXXVI:8 182: PCP combined with marijuana is referred to as Killer Joints, Super Grass, Fry, Lovelies, Wets, and Waters. Today, PCP joints are often referred to as ‘dippers’ because users dip the joints into a PCP-laced liquid referred to as ‘water.’.