Rudi, when I lived in Oz, "dags" was defined as the very dirty tail-end of a sheep. When they shear the sheep this part of the fleece (wool) gets discarded. As, "He's looking daggy." Please be careful about using this word!

How about "laughing at the floor" (the above-mentioned chunder...)

Or "wrap your laughing gear around that" (have a drink)

And another of my favourites, "I'll knock you up" (rap on the door with knuckles, what else?)

The first time I arrived in Sydney I was taken around to the home of some very colourful working class folks and I swear I could barely understand them! Struth, strine is fun!