there are different variations to grab your foot. I know four
1)I show the easiest one in my cocoon tutorial at 0:40: http://www.youtube.com/watch?v=PUyXF0MAu5w
right hand grab right leg with the palm facing to the ceiling, then you have to twist your arm and the thumb will point down
2)same as above but you grab the opposite leg (right han grabs left leg), again palm up and you have to twist the arm
3) I do it here at 2:03 http://www.youtube.com/watch?v=pXs6fe7tSKw
left hand grab left shin with the thumb up, pull it to your shoulder then grab it with the right hand (thumb down). let go with the first hand to bring your head to the hole between your back and leg and then grab it again (thumb down this time)
on the pole you would start in a twisted ballerina
4) the hardest for me, but it looks more simple and clean
you can see it here at 2:16: http://www.youtube.com/watch?v=AzlXNj3QbIQ&feature=g-u-u
you place your left hand on top of your right leg with the thumb up and just pull your leg up with a straight arm. I think it´s a bit similiar to shoulder dislocation, so you could practice these
Hope that helped a bit 🙂