Bacchus is the name Rome gave to Dionysus, and under the older Roman name Liber Pater he was one of the three gods of the Aventine, with Ceres and Libera, whose temple was the plebeians' own. His festival, the Liberalia of 17 March, was when a boy put on the toga of a man, and the wine-cakes sold there were the day's offering. The Bacchanalia scandal of 186 BCE, when the senate suppressed the god's Italian mysteries by decree, is the moment the Roman state drew the line between its own Liber and the ecstatic Greek god.
Modern Practice
Bacchus is called on at the vintage, at a first cup, and when something has to be loosened after a long restraint. His practice is the shared table and the honest drunk - with the Roman caution that the state once had to put the god's own revels under law.