Lily the Pink; Lilly noun a drink UK Rhyming slang, based on “Lily the Pink” a popular song which begins: “We’ll drink-a-drink-a-drink”.
“Oi, Bernie you kant [cunt] where we going for a Lilly?” “A fucking what?” “A facking Lilly the Pink, you slay-agg [slag]! — Kevin Sampson, Outlaws, p. 172, 2001