It's a Russian saying.
Their traditional vodka comes in a bottle with a cork. So when you open it, you'll drink the entire bottle.
If there's two of you, you'll be too drunk to order another bottle.
If there's four of you, you'll be too sober, and sensible enough to not buy another.
So you need three.
(, Tue 16 Nov 2021, 11:37, Reply)