Green’s Dictionary of Slang

haw maws n.

[rhy. sl. = baws, i.e. balls n. (1)]

(Scot.) the testicles.

[Scot](con. mid-1960s) J. Patrick Glasgow Gang Observed 76: More butts in the head and ‘boots in the chuckies’ (alternatively described in rhyming slang as one’s ‘haw maws’).