Answer:
Explain to your friends that this action is wrong and not accept doing that.
Explanation:
You should avoid drinking alcohol in this age (im assuming they are teenagers, because of the school) and you might advise your friends about the dangerous of start drinking early.
Adolescent alcohol consumption compromises the development of the central nervous system (CNS). In this way, your neuronal pathways may become more susceptible to alcohol damage and may impair several functions. The sooner you start drinking, the sooner you may have problems with alcohol: Studies showed that the use alcohol before age 15 are four times more likely to develop alcohol-related problems than those who start drinking after 21 years. Moreover, for adulthood, alcohol use in adolescence is associated with increased use and abuse of other drugs and more impulsive effects. Under the effects of alcohol, young people are more likely to take risks - including fighting, unprotected or unconsensual sex, car accidents, and etc. In severe cases, young people may have other negative consequences, such as alcohol use, such as not fulfilling important obligations and even legal, social or interpersonal problems.
So instead of doing that you should talk with your friends explaining how harmful alcohol could be and suggest do another thing, like play a game, instead of drinking.