So, yes, it is a very difficult pose to master and the pain in the ankle, to which I feel a strong resistance, has to be withstood before I proceed ahead.
But this is the first time, today, I caught on to all the mistakes I've been making and that makes it an interesting pose to relearn.
* It is better entered from a squatting upright position, even if you must use a blocks. This is a lighter entry.
* But here different sets of muscles get used. From a squat, you use upper back (which is possible for many yoga practitioners) but from a standing position you need pure hip strength, and a peculiar band of muscle along the hip. So, you may have to struggle with this stage -- with the leg bent -- for a while before you develop muscle memory and strength for that.
* The foot locks itself on the arm. It is better than getting it crushed mindlessly (as I managed to do till now!).The foot is not under the chest, but curved around the arm, in a hook.
* The shin bone of the bent leg also creates a pressing lock and that is how the leg does not slide off.
*It is better to learn strength with the back leg bent and do it for longer than crave an instant lift that is never satisfying and does not give you the right muscle memory.
This pose has taught me that sometimes it is better to unlearn everything and start afresh, with the mind cleansed of the mistakes and from another place (of entry) so the mind is not cluttered by memories that get in the way.