Shorthand for 'designated driver.' The person who escorts you to the club, drinks lightly if at all, and helps
drive you home after a long night of cirrhotic frivolity. D2s are
occasionally given
special treatment by bartenders for their services, such as offering snacks and non-alcoholic beverages to dedicated D2s.
Person 1: "Hey, can you be my D2 tonight?"
Person 2: "Sure! I charge $13 per hour, plus $50 if you vomit in my car."
Person 1: "What? Why are you charging me just to-- ...oh."