Begin with legs straight up, ball firmly squeezed between your feet.  As you release your legs to the side, let the ball drop straight down, catching it with your hands.  As soon as you catch the ball, immediately release the ball back up, as you pull your legs together.  Once your feet make contact with the ball, contract all of the muscles along your inner leg to maintain a firm grip on the ball.  Release and repeat.

Model: Alissa Schneider