AW C'MON, FAIR SUCK OF THE SAV, MATE!
"Fair suck of the sav" is an Australian slang phrase that basically means "You've got to be kidding!"
Being a multi-purpose phrase is can convey an attitude of unbelief , awe, wonder or even exasperation or frustration. The phrase 'fair suck of the sav' is like 'fair suck of the sausage', 'fair shake of the sausage' and similar Australian sayings meaning basically the same thing.
Some believe that 'sav' is a reference to the wine Cabernet Sauvignon which is often shortened to 'cab sav' . Either way the shortand really has nothing to do with the emotion being expressed in the sayings.
This leads to another explanation and variation 'fair suck of the sauce' or 'fair suck of the sauce bottle' whereby any bottle of alcohol liquor is often called a sauce bottle. This saying can often mean '‘fair go’ in that it expresses a keen sense of injustice - 'fair suck of the sauce bottle, mate, I’m only asking for a loan till payday!'
It is widely believed though, that the "sav" part of the phrase refers to a saveloy (a type of meat sausage) and that at some stage ‘saveloy’ or ‘sav’ was substituted for ‘sauce bottle’. The phrase ‘fair crack of the whip’ has the same meaning.
Whatever the saying, the phrase often means that you think a person’s comments or ideas are a bit ridiculous, a bit extreme, or even mildly untruthful. The Urban Dictionary gives this example...
Man 1:
"Pie and sauce thanks mate"
Man 2:
"That'll be seven bucks"
Man 1:
"Fair suck of the sav!"