In Monty Python terms, English upper class twits - public schoolboys who turn into oiks and behave rudely, noisily and foolishly in a group at public functions rather as European players of rugby football are commonly said to comport themselves at social events. The females of the species (rarer)are Hooray Henriettas.
A cultural phenomenon, to be a part of which includes becoming sufficiently hounded and clubbing for those cognitive enough. The night ends deep into the AM at the persons house closest to the city, and the morning after involves watching tv and feasting on mcdonalds breakfast.