Blame It On The Alcohol (E36)
In this episode, the kids try to promote not drinking by singing a few songs having to do with alcohol and the cons of alcohol.
However, the kids themselves drink just before performing and vomit all over the stage, leaving the school disgusted and, ultimately, dropping in alcohol lovers. To their surprise, Principle Figgins appreciates the "act" they performed and thanks them for their help. Will Schuester, however, was not so happy.