Green’s Dictionary of Slang

1. (Aus.) a drink.

1967		‘Whisper All Aussie Dict.’ in Kings Cross Whisper (Sydney) xl 4/4: slurp: A drink.
1992		Guardian 22 Feb. 31/4: The purpose of a night on the slurp is [...] to get gone.

2. fellatio.

2011

G. Hayward Corruption Officer [ebk] cap. 31: I needed a bill paid and he did it for a two minute slurp session.