World's best left trot (starry eyes)

John said that MAYBE next year we can do 1/2:1/2 at the shows, where he rides Duke then I ride him.  He said we'll see, but that the downside is he'd turn Duke into the type of horse he'd like to ride, and then have to ride him all season.  That actually probably wouldn't be too bad with the new job.
He said that to ride prelim, I have to join USEF. Which means I have to watch their videos.
He said that if I'm buying Duke a new girth, get him one with a belly guard, just to avoid injuries.
And then for the lesson.  Duke moved great, and he felt amazing.  I could feel when he softened and bent and started using his topline.  He seems to want me to use the upper part of my calf to squeeze and then keep him from moving away from my leg by using the outside hand in a little bit of a reciprocal squeeze.
We worked on 10 meter circles, where John had me counterbend, then cross his front legs (so he was moving towards John) and then allow the correct bend, and then, without changing anything, to leg yield back out to a 15 meter circle.  He picked up the canter on the 10 meter circles, and we had some decent (not amazing) canter/trot transitions.
But it was the lifting up and using his back that was just so amazing, like the left trot was just so amazing to feel that I had trouble listening to John for a little while and just wanted to ride around and around doing it.
For the canter, I didn't think cross his legs, but have his outside leg come under the center of his body (front leg).
Duke was sweet and obedient during the lesson, but when I went to get him in his pasture this morning, he ran away from me and acted like it was because he's so attached to Ellie.  That annoyed me.
I felt like I rode this better and more consistently than some of our prior lessons, but I still need John's help with each specific aid (outside leg back and on now-now-now) to get Duke to respond correctly, and I can feel it when he does, but I'm still struggling to put it into words in this summary.
Christa told me that John is harder on his upper level students and expects more, and I think that's what's going on.  He's taken it up a notch and it's all new to me so I'm struggling to keep up.  But if this goes like his other lessons, eventually I'll make it rote and then we'll work on the next thing.