Alternate (read: slightly more studly) name for the man-purse, murse, messenger bag or "satchel" that straight or metro guys try to get away with carrying these days. Usually is made of canvas.
Comes from the Australian term "swag", a waterproof bedroll that foot-travelers used to roll up their possessions in for safekeeping and easy travel.
"Hey, Brett, check out Hunter's man-purse. He's such a prep."
"Naw, dude, don't you know anything? That's totally a guywag."
"What's a guywag?"
"Check urbandictionary and find out yourself, you lazy slacker."
The ability girls and women have developed to hold several items at once in one hand. The skill has been developed due to the lack of pockets in women's clothing.
I thought she'd need multiple trips to carry her phone, keys, wallet, and Starbucks to her car since she needed the other hand to open the door, but she used her impressive girl grip to carry everything in one hand.