Something must be clicking, because just this past week I feel that my sirsasana I is finally becoming the pose it's supposed to be. Previously, I had been trying to balance hovering an inch away from the wall, but it was terrribly filled with effort, stress and fear, as well as that telltale grinding and creaking in my S/I, telling me I wasn't engaging my body properly. Plus it felt like I was dumping all my weight onto my head, very bad, I know. And it's not like I don't have the strength or body-awareness toward proper alignments, because my sirsasana II has been effortless and correct-feeling, in the middle of the room, since the first time I tried it (lifting up my legs in a straddle from prasarita padottanasana, actually).

So I think I know what I'm finally starting to do right (though I'm open for feedback and suggestions as well, because I know I'm not 100% there yet): shoulder loop and shin loop, if those Anusara terms mean anything to anybody. I had been trying to firm all my muscles in my core and find the stability from there, but no amount of "firming" was keeping that grinding in my lowback from happening (feels like gears struggling to mesh but not slipping, quite unpleasant). I had tried focusing on squeezing my legs together at the midline, as well as activating my feet, but still that did nothing to improve my stability as well. All the postural alignments weren't helping me, and even when my teachers would observe me, they couldn't figure out what I was doing wrong (or not doing right) either. Quite frustrating.

I think the breakthrough happened while working on pincha mayurasana, another pose I've always had difficulty with, when I finally figured out how to keep my forearms really engaged into the floor. Did I mention that I have a shoulder thing too? Very tough for me to keep my right shoulderblade drawn down into my back properly, due to surgery I had on the joint several years ago. So that's why I've tended to stay away from forearm balance, thinking that having such tight shoulders would make that pose inaccessable to me. But then I read in the Anusara teacher training manual that pincha mayurasana is a pose that's taught at the beginning of class with the intent to open the shoulders, and I thought HUH? Don't you already need to be open to do the pose? Guess I was wrong there, and happily so.

So... what I learned was how to firm my forearms, i.e. how to engage the muscles to the bone in my arms ("shrinkwrapping" the muscles to the bone is how I find myself thinking about it) and up to my shoulders, thereby activating "shoulder loop" and setting up the proper positioning of my upper body. Shoulder loop is one of the ways how muscular energy is engaged (that shrinkwrapping and firming effect), along with shin loop (moving the tops of the shin bones forward, sort of preventing a locking of the knees, among other things), so I tried to focus on both those aspects at once the other day as I tried my headstand. And that was the missing link! Not more work in the core, or a better tucking of the tailbone, but in the shoulders and the shins! Who knew?!

Grinding your teeth, maybe? The focal point of the pose is the upper palate, so if you felt stress in that area, that kinda makes sense because of the work that's needed there, even though you're not supposed to be having pain (duh). I'm still all very new to this, but my instincts tell me that if I had that sort of reaction, that means that I'll not drawing my palate back enough;or better yet, that I'm allowing the origination of energy to be a touch too far forward in the jaw area. Any of that make sense? The instruction I would give to myself in your case would be "take it further back in the skull", though to explain what that "it" is, I have no clue.

Oh, and here's one more insight that might help (or not): the flow of energy for the shoulders connects through that same point in the upper palate (shoulder loop and skull loop), so for me, I find it helpful to remember that intersection point, maybe even visualize it. Lots to do when you're upsidedown, for sure.