Charlie earned a "wow"

We had an amazing dressage lesson today.  It was all the more amazing because although Charlie was better at home this week than last week, he certainly wasn't full of zest and vigor.
John had us work in draw reins on several 10 meter circles, sometimes with just a bit of a bend to the outside, followed by some lengthening.  Then he added in canter circles, followed by canter lengthening.  I don't know why, but Charlie was willing to just spring forward into the lengthening.  We even had a moment where he rocked back and was using his haunches!  John also had me sit the lengthened trot, which makes me bouncy, and he said to think about hips going "right left right left" so that I don't impede the movement.  He said that it's rough, but that it makes my back loosen up afterwards.
Unfortunately, I am not sure why Charlie was such a rock star today.  He was a bit of a slug yesterday in the jump saddle, and I thought that was because he was sore from the day before, when we worked in draw reins at home.  There certainly wasn't any hint that he was going to pull out all the stops and be flashy.
We did a few trot 10 meter circles with a  change of direction in the center, and we also would do a 10 meter circle and then a shoulder in.  John said I was using too much hand and needed to bend him from the inside leg.
John said that our shoulder in is much better, that I don't have to struggle to keep it, although I could feel that I would lift the inside seat bone (and shift to the outside, to try to push him over) so I need to be more aware of that.
In the canter, we would do a hint of bending to the outside, and then lengthen even with the outside bend.
At the walk, I have to give a little forward with my hands, and then I give with the opposite hand from the leg (so if my right leg is active, my left hand gives just a bit) when he is walking with the mincy steps in the draw reins.  To make his stride longer, I swing my hips bigger.  Charlie responded to this like he'd been waiting for me to do it.
John suggested that his tip last week for the sluggish canter was probably to try a bit of haunches in at the canter.  We didn't need it today, but I bet I'll get a chance to try it this week.
John said for dressage, it is best for Charlie to do short bursts that are hard work like this (he had frothy sweat under his girth - I had to flick it when I took it off), and then build his stamina with trot work in the jump saddle.  He said that it is possible to do two long formats in a year - that Rebecca in July and Galway in November would probably work, but we need to wait and see how Charlie is doing.  He said the one star speed used to be like 620 mpm!!
As best as I can tell, Charlie was just in a mood to work today, but I will try to repeat the sequence of exercises to see if there was something about it that helped Charlie to get in the proper frame, and frame of mind.
John gave us a "wow" for one of the canter lengthenings.  I think it is the first wow we have earned that is not a "wow you are a bonehead" wow.  Charlie tripped a few minutes later in front of John trying to do a down transition, so that evened things out.