the one motherly girl amongst the group who can still take care of friends (hold hair while friend throws up, walk friend to the restroom to piss, make drinks, carry/walk friend, etc.) while being drunk herself and not being bothered by it at all.
Girl: I really hope I don't get drunk and stupid at that party tonight.
Boy: Don't worry Diana is gonna be there. She usually enjoys playing the role of Mother Grey Goose when we're out at parties.
First, you and three of your friends stop at a garage sale to avoid having to work out at track practice. Next, you find a broken cement goose sculpture being given away for free at that garage sale. Then, you and your friends carry the heavy goose sculpture over a full mile of hills back to your school track/football field, even though it would have been much easier to drive the sculpture back in your car.
Coach: What is that?
You: It's a cement goose. Instead of running, we were walking the goose.