So you've seen all your friends playing flip cup and other drinking games, and you don't really want to play. It's not that you don't like to drink, you just aren't good at it. What are you doing wrong? Basic physics my friend.

Remember the basic physics laws you were taught in high school (what goes up must come down, for every action there is an equal and opposite reaction, etc?). The same applies to drinking beer. For every liter of beer that you drink, the same amount of air needs to leave your mouth.

Many people do not realize this, so they create semi-seals on their beer bottles and don't leave room between their top lip and the beer when using cups. Why does this matter?

Flow, of course.

When drinking out of a bottle: your mouth should never take up more than 3/4ths of the drinking hole. This leaves enough room for the air to escape your mouth (and flow into the bottle)

When drinking out of a cup: you should leave at least an inch between your upper lip and the beer.

So now that you understand how air flow helps, lets talk about the actual act of drinking out of a cup. You should first be prepared. Breath all of your air out, so you don't need to breathe in. With a bottle this will let you drink for a longer period (opposite with the cup).

Breathe all of your air out before you drink. The key hear is relaxing your throat. Tilt your head back until your throat is relaxed, and pour the beer. Try to swallow without pushing beer the wrong way (out your mouth and onto the floor).

Good luck!