Chomping at John's

For the first time (?), Duke did his bit chomping thing at John's and stayed pretty tense all the way through his lesson.  It was good, because John got to see it, but I'm not sure what caused it.  There were other horses finishing their lesson when we started, but he stood calmly and didn't seem to care much that they were there (or that they left).  Maybe he was just crabby from finally getting a day of turn out and it only lasted an hour.
We worked on different sized circles, with John helping me again with each aid (each hand, each leg, and sitting up) timed to match what Duke needed.  There was a bit of a eureka moment, where I could feel the connection from outside leg to inside hand, and then could feel how to keep Duke between my legs, and that my legs really could direct his line of travel, and I didn't need my hands (as much).  That was pretty cool, but only lasted for a moment and was gone.  However, I felt it, so now I know what it feels like.
John had us do several short transitions - he'd say "trot", we'd trot just a few steps, and he'd have us go back up to canter.  Our transitions weren't that great, but John said Duke did better about not flinging his shoulders so far out, like he was doing last week.
It was a great lesson, but frustrating that I am so slow to pick up on these fast aids.  It is going to take me a while to be able to ride Duke every step like John can have me do in the lesson.  Hopefully it's not an impossible task.  It's great, because he's so nimble and reactive, but man, when I am riding at home, I am basically a dullard compared to what happens in the lesson.