Dressage in the sun

We rode in the nice April sunshine outdoors today. John had us work on "half steps" at the walk, then used it at the trot and canter. It's a different term than "collect" but I think has the same meaning; get Duke coiled up and then have him go forward, but with the energy coming from behind and up and over instead of out the front.
We started on a small circle, John took the reins to get his frame, and then I tried to replicate it. We did half steps, and tried to have him bend his body, not just his neck. The aids were easiest at the walk; I could hold my lower leg on and kind of lift him into my pelvis. I am not quite sure how to describe it. The hard part was to keep my seat moving; if I held my leg and didn't move my pelvis, he'd come to a halt.
At the trot we worked on the same, on the frame, but then added leg yield out to make the circle bigger. John said he wanted Duke's hind legs to cross; he wanted him to really step across himself. Here, he had to tell me to put my shoulders back, or to sit 4 degrees further back. I would roll forward.
I had to give different aids with everything - each hand was different, each leg was different, the seat was doing its own thing, and my shoulders something else. It was hard to keep them all in my head at once.
But it was worth it, because after the canter, we did the long side and we lengthened, and I could feel Duke lift his shoulders to kick his front legs out. This is three times now, maybe four, when I've felt it. It feels amazing. I can't believe Duke can do it. The first time, John had been riding him. But the second time, John walked me through it until I got it myself. The third time was at home, a surprise I got it at all. So today was the fourth.
Before that we cantered, John wanted transitions with no head lifting up above the bit. But I don't know how we got them; I don't remember the sequence of movements just before the aids. For down transitions though, it was the half step/collection and then holding my leg and pushing him down into the lower gait.
At the canter, it was hardest to keep my seat down, to keep my body leaning back. It's really not my seat, it's that his head pulls my arms down and I can either slip the reins or I can tilt forward. So that's good, if I know what is causing it, I can recognize it and stop it earlier. It's just thinking about sitting up/leaning back/someone pushing my collar bones back.
I could feel when Duke went over the top and got soft.  That's when I'm supposed to give with my hands. And when I did, he would lower his head, chew down.
I asked John after about Freddy - is it his body, his mind, his training, Alina's riding? John said it's like Michael Jordan; some horses are just very talented. He said if you ask him with your reins to do something, he holds it until the next thing you ask him to do.
I was impressed with Duke. I don't feel like I've been working him hard enough or consistent enough to be getting this good of movement out of him without John on him.