strop, v. — Green’s Dictionary of Slang

strop v.

[SE strop, to sharpen a razor]

(Aus.) to masturbate; thus stropping n., masturbation.

1990		Tupper & Wortley Aus. Prison Sl. Gloss. 🌐 Strop. To masturbate.
1999		G. Seal Lingo 126: Beyond the general Lingoisms for masturbation, such as STROPPING and WANKING, this act seems to inspire us to poetry.

strop (n.) (also stropper)

(Aus.) an insult, the target being classified as second-rate.

1985

‘Thommo’ Dict. Aus. Swearing & Sex Sayings 126: STROP — Short for stropper. A male that doesn’t have much meaning in life.