This is the finger drinking game. All you need is a cup and your friends and their beers. Now, all the friends sit around in a circle and each player gets to pour as much beer as they want into the middle cup. Be aware that you may be drinking this beer at the end of the game and factor that into your decision of how much beer you pour into it. Now, everyone takes their right index finger and places it on the lip of the cup.
Now, for teaching sake I'm just going to teach you with just two people, two players. That will be usually closer to the end of the game because you'll have, you know, four, five, six, ten players playing. Each person puts their finger on the lip of the cup and you have the choice to either leave your finger or remove your finger. Now, how the game works is that the first person will say one, two, three and then any number between zero and the number of finger on the cup.
So, for this it could be zero, one, or two. Then, both players have the option to leave their finger or remove their finger. So, an example: one, two, three, one. Now, if I'm this player and I said that and I removed my finger and this finger is the only one left I win. I was correct about the number of fingers left. So, say there's six fingers around the cup and you go one, two, three, five and everyone removes their finger from the cup you lost.
So, it passes on to the next player and the next player does the exact same thing; they say one, two, three and then they say any number between zero and how many fingers are still on the cup. If you guess correctly, meaning the number of fingers left on the cup is the number you said, you can remove your finger from the cup and you are safe from drinking the beer at the end of the game.
So, essentially the last person with their finger still on the cup has to drink the beer at the end.