Green’s Dictionary of Slang

slush v.

[backform. f. slushy n. (1)]

(Aus.) to work as a cook or cook’s assistant.

[Aus]Sun. Times (Perth) 2 Feb. 1/1: Her daughter [...] slushes in an egg-flippery.
[Aus]Sport (Adelaide) 13 Nov. 5/5: Sid W has left off wharf work and is taking on slushing.