To Hop up on the toilet seat and squat like a Kangaroo when taking a dump. Often done out of fear of catching a VD of the toilet seat. Please note the two definitions provided by James Brick and PaddyM are actually incorrect and are discribing a Reverse Kanga, a witty practical joke that will keep your friends amused for hours)
Shit this crapper looks dirty, i better go the kanga.
1. "Fuck Robbielard, that kanga is damned nasty. Brat's gone in there and eaten it, the turd burglar he is," Wobs exclaimed.
2. "FFS, i've got a fucken kanga," muttered Von as his assbled from a metaphorical anal raping.
To sit facing the rear of the toilet and defaecate onto the front side of the bowel. This act is specifically designed to leave a trail, or skidmark down said bowel. It is usually carried out as an offensive gesture towards the next occupant, or the owner of the crapper. Popularised in Australia after reference on Big Brother 5.