Green’s Dictionary of Slang

1. (Aus. juv.) the penis.

1985

B. Arndt Aus. Way of Sex 13: ‘[O]n a Sydney radio station talk-back programme, a caller referred very delicately to a man’s ‘apparatus’. I am glad my children did not hear it. I would have had to explain that it means ‘diddley’ [Simes:DLSS].

2. see also under diddly and its combs.