Pitiful helpless left hand

We worked more on the hard circle today - going to the right, spiraling in - and were able to further identify the problem. While I can put my left hand up the neck no problem, when I try to put my right hand up, my left hand follows it. And if I try to hold it still, my whole body bends to try to follow it. We did a few other exercises where all I could feel was that terrible limp left hand not doing its job, like riding in a straight line in the canter off the rail, and we'd just drift, drift, drift to the left because my left hand couldn't "block the water" like the Centered Riding analogy has for the hose. Shannon made me first try to bend each way (couldn't bend to the left) and then ride a leg yield (?) in to the right off the left leg, which forced my left hand to clamp down and my left leg to do its job. It was a very good, but very frustrating lesson. When we peeled that layer off the onion to "polish" I had no idea how difficult this next level was going to be. I can't wait until future me is looking back and reading this and being relieved that the phase was over with. In other words, keep the faith present Martha.