The ancient Roman god Bacchus was no teetotaler. A bacchanalian party is a wild, wine-soaked, rowdy affair. Bacchanalian is used to describe any event that Bacchus would have enjoyed.
The Romans celebrated Bacchus with wine, songs, dances and more wine — not the kind of behavior you would expect from self-respecting adults (and probably not the kind of thing they would tell their kids about). Another word for bacchanalian is Dionysian, in honor of the Greek god of wine and crazy parties. Any kind of wild revelry can be described as bacchanalian.