Wiz Khalifa & Amber Rose -- It's The Man's Job To Push

New parents Wiz Khalifa and Amber Rose have figured out how to divide their parenting chores -- he pushes, she carries.

The superstar couple -- who married this past summer -- went for a stroll yesterday in West Hollywood with their son, Sebastian, who turns 1 next month. Wiz pushed the empty stroller ... while Amber did the heavy lifting.

Amber says it took her almost a year ... but she got back to her pre-baby shape ... by working out every day.

Lookin' good.