You take it out of the fridge and down it one shot at a time from a shot glass. Of course, if you don't have a shot glass, you can be like my friends and just use a beer glass, but its definetly not recomended. The stuff is quite strong, usually 20% to 25%, and honestly, smells (and tastes, I'd imagine) exactly like rubbing alcohol. Not very pleasant, but hey, at least it has more "zip" to it than beer.
And how do I know all this? My Korean friends drink this stuff like water so when I'm with them they always choose soju. And to Croton, alcoholic koolaid? Yummy alcoholic koolaid? You must have had a bit too much to remember it as that 😀