Green’s Dictionary of Slang

1. to urinate.

1996		N. Blincoe ‘Ardwick Green’ in Champion Disco Biscuits (1997) 10: There were two lads wazzing up against the piss stones.
1997		Roger’s Profanisaurus in Viz 87 Dec. n.p.: waz v. variously To piss; to puke; to wank.
2017		Times Times2 6 Jan. 🌐 After nine hours of booze on a hot and dehydrating day, you’re wazzing something that looks like jam.

2. to masturbate.

2005

Roger’s Profanisaurus Rex 334/2: wazz [...] to wank.

3. to waste.

1999

Indep. Rev. 30 Sept. 8: Who wazzed all the money?