Whip position started at frontend
Leave the platform with your hands closer than for a normal swing. At the frontend, bring your legs up in front of you, pass them through your hands place the soles of your feet on the bar in between your hands*. At the backend, straighten your legs, so your legs are together in front of your head. Head should be tucked in. At the front end, unfold your body to catch. * This trick can also be performed in 'one position'. Make the final position immediately at the frontend, hold it as you swing back and out again, then open as usual.
Notes: Whip in two positions (preparation, final)
You can find out more about this trick in following books: