A way to say "Hi" to your friend.
A way to catch somebody's attention
The best thing to yell at people, or crowd of people while riding shotgun in a car.
1. YOU: "Yo Bag! How have you been"
ME: "I've been good, yah' bag."
2. "Yo bag, can you call my phone? I think the couch ate it"
"Dude, why do you always lose your phone?"
3. "YO BAG!"