wentworth falls, n. — Green’s Dictionary of Slang

wentworth falls n.

also wentworth’s balls

[rhy. sl. = balls n. (1); ult. the Wentworth Falls, near Katoomba in the Blue Mountains of New South Wales]

(Aus.) the testicles.

1984

Partridge DSUE (8th edn) 1318/1: Wentworth Falls; Wentworth’s Balls. Testicles. Aus. [...] since 1920.