(Australian slang) The act of pulling someone's pants or shorts down when they least suspect it, usually by sneaking up behind. Intended to cause maximum embarrassment, particularly if the "double dacking" is deployed, which also removes the underwear, exposing genitals.
A typical form of humiliation or payback in school yards in Australia.
Young Steve was talking with a group of sheilas he wouldn't mind having a crack at one day.
Suddenly, Dave emerges from behind and gives Steve a dacking.
Steve: Oi fkn *frantically grabs at pants*
Dave: GUEHEHHEHE
Girls: *titter*
Tracksuit pants. The lower half of a tracksuit. Often worn in Australia instead of shorts, trousers, jeans, skirts, dresses, slacks, etc, because they are comfortable. Acceptable attire amongst family, friends and neighbours (everybody loves good nieghbours). A derisive term when applied to strangers.
"I don't care how muuch you paid for your jeans, only fat cunts would wear their 'tracky dacks' in public!"