Green’s Dictionary of Slang

(Aus.) the penis.

1967		A. Seymour One Day of the Year 50: ‘Says here the Pope as a young man was quite good-looking. How do they know, they haven’t seen his eric?’.
1985		B. Arndt Aus. Way of Sex 10: By the time I had left school, I had heard most of the euphemisms. There was dork, eric, muscle, [...] tonk [Simes:DLSS].