Trollosuke said: I...don't think that position is possible..
It is. Its just painful as hell (and potentially dangerous) without months/years of practice.
Lay flat on your back, lift your legs straight up then let them fall towards your shoulders while bending your knees. Once your knees are at your shoulders and the sides of your head, turn your legs as if you're preparing to sit cross-legged behind your head and hold that position.