Phonetic spelling of Joz, australian slang for a joint. Some Australians think it clever to replace the 'J' sound with a 'Y' sound, giving the word a swedish quality. Thus furthering the stereotype that australians are in fact, culturally retarded.
Stoner #1: "Yo dude roll us a yoz..."
Stoner #2: "Fuck man, that sounds swedish, you're like swedish or something."