D.U.I. (Driving under the Influence) song meaning

This song is about getting drunk and going out for a drive. The narrator describes all the consequences of driving under the influence in a joking manner - "let's go down and vomit out of the window, let's keep score of how many we kill". He wants to have an ultimate kind of fun without thinking of what's going to happen afterwards - "we're going and we're never coming back".