Bau was a word invented by rich snobby boys on Oslo's (norway) westside. Later, it got spread in the whole Eastern part of Norway, and now it seems it will be a common international word. The word itself means snuff (norwegian/swedish: snus), which is tobacco you put in your upper lip. The word was made to keep the snuff orally hidden from the parents (as the kids who invented the word, and used bau, were underaged and therefore not allowed to use bau)
Can I have a bau?
Did you bring the bau?
Yo! I just be chillin with a bau!
Norwegian: Kan jeg bomme ei litta bau?
Norwegian: Tok du med bauen?
Norwegian: Jeg chillern med bau.