Come the raw prawn (with someone)

Raw prawn is an Australian metaphor for an innocent or novice, particular a raw recruit in the armed forces, whence this expression is thought to derive during WWII. As in all these ‘don’t come the….’ expressions, which are used in response to some attempted dodge or other, this one was thought to have originated in the Australian armed forces where raw recruits were always trying something on. See come the old soldier.