What is Raw Prawn?
1.
From the traditional Australian expression: "Don't come the raw prawn!" or "Don't come the raw prawn with me!", meaning: "Don't try to put one over me!" or "Don't treat me like a fool!".
Particularly used to indicate that the listener is aware of the speaker's ingenuousness, for example where the person to whom it's directed feigns innocence or naivety.
Etymology:
Some sources say it is a WWII Australian Army expression. As to why it arose: one suggestion is that the reason lies in cooked prawn being more palatable than raw prawn. However, anyone from a fishing background who has handled raw prawn flesh, will know that it is limp, wet and slippery; like the sort of people at whom this phrase is directed.
Manager: "I'm sorry, Dave, management has reviewed our operational requirements and found that your position cannot be justified financially".
Employee: "Don't you bloody come the raw prawn with me. I know it's you who wanted me out. At least have the guts to tell me to my face".