Teresa,
You are right, as a verb it does mean to act the clown, to engage in practical joking.. However, as for so many Aussie slang terms is has multiple uses and in my post is was used as an adjective, describing a reversal of the expected norm, doing things backwards or out of logical order... It can also be used as an adverb to mean an about turn, or sudden abrupt change in thought, direction or motion. I'm sure there are more... We are lucky 'down under' in that if a phrase seems to fit, it will!!! And I'm not arsing about!!!
Hugs,
Donna