Kiwi 'kustoms'

I have a cousin who lives in New Zealand and married someone from South Africa.
SO when watching travel shows or sports (wrestling as there is a south african one in the WWE named Justin Gabriel) sometimes you hear them say something in their native tounge but what does it mean?

So I thought my friend's blog on Kiwi english (that would be those from New Zealand. ) would be a good idea. I found it to be quite amusing and entertaining.. being apparently Kiwi's 'piss' alot! You will see what I meen by that in the 3rd paragraph. 

My question though is here we sometimes say someone is a pisser if they are being funny what would that be there!? and why not say fanny? (I think its a funny word) and root.. well I can actually get that as an expression.
Top 10 FUNNY New Zealand language blunders-Beware!

Also some Kiwi vs American English