Green’s Dictionary of Slang

(US) to drink.

1911		T.A. Dorgan in Zwilling TAD Lex. (1993) 83: They tipped over a few at Gregory’s gin mill.
1914		T.A. Dorgan Indoor Sports 14 May [synd. cartoon] Indoor Sports — Sneaking Outside to Tip One Over.
1931		W.N. Burns One-Way Ride 56: Let’s sit down and tip over a mug or two.