Pilates with Beth

I had my second dual mat session followed by a lesson with Beth Glosten today.  Like our prior mat sessions and riding lessons, it was tremendously useful.
The quick version of what I need to think while riding is the feeling of a rope around my waist pulling me to the right.  The second "clue" for correcting my position is when my right leg starts to curl and stick tight to the saddle.  That is my reminder that I am too far to the left, and I need to put my weight back into my right leg, which lets it relax and then be a useful aid.
The more complex version to fix my funny sashay twist is this:
1.  Use my left hamstring, plus the push up in the posting trot, to push my left hip up.
2.  Keep my left toe from moving forward, to keep my leg underneath me.  Using the hamstring properly kind of solves this one on its own.
3.  My hips need to make a plane with an angle that feels like it is with the left hip back and the right hip forward.  This is easiest to think about pushing the right hip forward (instead of pulling the left hip back).
4.  Then my left oblique muscle needs to shorten/engage.  This is the hardest one to do.  This one helps to think of the criss cross from the left hip to the right shoulder.
5.  Continuing to move up, my left shoulder comes back and my right shoulder comes forward.  This makes my sternum ride in the same plane as Charlie's.
When I manage to get all 5 of these together, the sashay gets dramatically diminished, and there is less wiggle in my spine.  But as soon as I drop one (usually the oblique, which then very quickly results in the toe moving forward), the sashay is back with a vengenance.

It sounds simple, but I think it is going to need some real concentration before I start to get the muscle memory and don't have to think so hard about it.  It is one of those things where I have to stick my tongue out while I am going around (I actually had my tongue out while I was typing it!) because I am concentrating so hard.
The oblique is really tricky.  I don't have very good control over it, so sometimes it responds and sometimes it doesn't.  What was useful was that it was the same way in the mat session, so it isn't just when I'm on Charlie.  Beth also gave me some great exercises to work on at home, to help strengthen it and feel it.
The good news is I can feel the sashay, which I couldn't the last time I visited her, and when we rode around with one stirrup dropped and then the other, there wasn't nearly as dramatic a difference as last time.
We did a bit of work on upper body, getting my shoulder blades together and then pulling down my back, and then sitting leaning forward just a bit.  I very quickly round up when I am concentrating on other things.
We also did some work at the canter, and Beth said the same as my dressage tests, the left canter is not as good as the right.  But she showed me how it was a lot of extra wiggle in my spine, and when I got everything lined up, all of a sudden it was amazing.  It was like I had Charlie's shoulders up between my legs so I could have turned him right or left or forward or back, and I was just completely stable and perfectly in place.  It was divine. 
I'm really glad to be so fortunate to be able to work with someone who can help me with these weird little quirks.  I want to get them resolved so that we can keep progressing and don't get hung up later because I ignored the problem.