Green’s Dictionary of Slang

beer and sarse n.

[rhy. sl. = arse n. (1); ult. sarse n.]

(Aus.) the buttocks.

[Aus]R. Aven-Bray Ridgey-Didge Oz Jack Lang 7: He pegged her up and down and lamped that the tight shorts she was wearing made her beer and sarse appear like two apples in a wet paper bag.