1. First, you want to just flop on top of the ball
2. Walk out on your hands until the ball meets your shins. Make sure your legs stay tight and your toes pointed, or this exercise will not work! Keep your arms shoulder width apart!
3. Fold yourself in half! Push your bum up into the air, keeping your legs as straight as you can! Its very important to push you armpits in the direction of the ball. If you don't, your weight will push you over the opposite way... into a painful summersault! Keep your toes pointed! Hold for about 5 seconds, unfold into position number 2, and repeat :)
I usually do about 15 reps, 3 times. A total of 45! This is a great exercise you can do at home if you don't have time to go to the gym! Make sure to drink lots of water :)