The bladder from a cask of wine. The name originates from bogans but has become more widespread as it is a very useful word. Bogans, uni students or anyone else prepared to drink it tend to celebrate how bad it tastes and just how lacking in culture or refinement the whole task of drinking it is. Such people will not call it a bladder of wine as they are familiar with the taste and don't actually believe that it's anything to do with wine. The fact that the box tries to convince you otherwise is probably a reason for the practice of discarding it and just carrying this bladder. The liquid being drunk is called goon