But the main thing is (in my diligent research) I came up with an authentic Aussie term:
The Toongabbie Backhand
Actually, I think this is a specific technique rather than a general term. It refers to (so the Aussie said) reverse hand manipulation, and may well have originated in New Zealand or with the Maori tribesmen, as a rite of passage. This latter is more likely, I think. At any rate it is said to be quite common in the western suburbs of Sidney. Sidney, incidentally, modestly claims to be, bar none, the wanking capital of the entire world. Hmmmm.
I will leave the particulars to your imagination.