How to drink more and not get sick?!
Eat something beforehand, especially something with carbs, like bread. The food will absorb some of the alcohol. I get stomach aches from drinking before I can get to tipsy, but eating helps. Also don't listen to anyone who tells you, "beer before liqueur makes you sicker, liqueur before beer, you're in the clear." It's a myth. Alcohol is alcohol. I read an article about it in a science magazine.
You also might want to try ways to get the alcohol to hit you harder. For example drinking out of a straw (though it looks kinda weird) makes the alcohol go to your brain faster. So you feel more of an effect for a smaller amount of alcohol, and thus shouldn't get as sick.
Why on earth would you want to drink more? The motto should be "party till you're prime" not "party till you puke". It doesn't make you any more masculine or cool if you can drink more alcohol. In fact, it kind of makes people that drink a lot look like losers. You don't have to get totally smashed to have a good time. Really.
Have you ever heard of alcohol poisoning? It will kill you. Getting sick is a warning that you have drunk too much. 5 beers is too much.