Nice term to describe anyone designated or willing to stay sober at events involving
alcoholic consumption. Basically, a nice way of saying, "don't worry my
friend, I'm staying sober- so you don't have to! Which means I'll be there at the end of the evening to question that '
date' you picked up, drive you home, and provide adequate support for you're drunken heap of a body... well go on then, get drinking!"