Green’s Dictionary of Slang

1. (US) the penis.

1998		K. Sampson Awaydays 131: Tongue-plating, good. Dobber, bad.
2001		K. Sampson Outlaws (ms.) 7: Lad had a big mad hairy dobber on him.
2003		N. Griffiths Stump 110: As long as I didn’t have to lose me dobber ’m not bothered.

2. (Aus.) a semi-erect penis.

1999

Roger’s Profanisaurus 3 in Viz 98 Oct. 3: Baccus Marsh n. A dobber From the spongy area halfway between Ballerat and Melbourne (qv).