You can also use a gymnastic mat, which you can buy at sporting goods stores. Go for a gym mat that is long and at least 6 inches wide.
Instruct her to then place weight into her hands and bend her elbows.
This will help you to determine which foot she should lead with in her cartwheel.
Make sure she leads with her right foot as she tries to cartwheel over the cushion.
Tell her to draw an imaginary line from the heel of her front foot to the big toe of her back foot.
Instruct her to put the weight into her hands, bend her elbows slightly, and kick her feet over. You may have to support her by holding on to her legs as she tries to go over on her first few tries.
You can also use a carpeted area, as long as there are no breakable objects or obstacles around.
Instruct her to get into the lunge position again, with her lead foot outside the front hula hoop and her back foot inside the hula hoop. Make sure she raises her arms over her head and puts weight into her front leg. Have her aim for the drawn hands in the second hula hoop as she rotates over into a cartwheel. Check that she finishes the cartwheel in the lunge position, with her lead foot behind her and her arms in the air.