A fat woman who kicks her stomach around like a ball. Not that she can help it but, her stomach is usually hanging over the belt line and over her legs. So when she walks it creates sort of a kicking movement. She is more than likely a mom, so when people see her they yell soccer mom
"You see that?"
A fat woman has just walked out the store. She's struggling to get to her car.
"It LOOKS like she's kicking her stomach."
"Yeah, like a soccer ball."
"Yeah, she's a soccer mom