I don’t know what “goon”is, but I want some.
Maybe only 5 cups though.
I can feel the hangover through the internet: https://delishably.com/beverages/Australias-Most-Famous-Drink-GOON-backpacker-travel-drink-alcohol
Box wine (cask wine or boxed wine) is wine packaged in a bag-in-box. It is sometimes called goon, and goon bag in Australia.