staying sober- so you dont have to!

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!"