Unconventional approach to Charlie's reluctance to bend

Today we had our dressage lesson out in the cross country course, which was great practice for the footing for the show this weekend, and the extra attention issues.  What I did NOT do was ride without my whip, since we can't use it for champs.
Charlie remained reluctant to bend, and - who knows why - I was having a terrible time sitting the trot - so John had me use my inside hand like a side rein - slipping it a little, then using my thigh as a block so that he would keep the same pressure, then pushing him off of the inside leg (or whip).  It was "unconventional" but designed to break his mental block about bending.  We would do a circle or two with his neck bent (it was much, much easier to bend him to the right so we mostly worked to the left) and then go back to regular reins, and I could feel his shoulders lift and the balance improve.
John said it would be useful for me once I'm back at home, so if Charlie gets mentally stuck, I have some tools to try to break it myself.
It was insightful, but really hard to do.  I was particularly uncoordinated at using my left leg and right hand at the same time.
In the warm up, unlike Sunday, I was NOT able to get a flying change each direction.  I could get the hop and skip, but not the actual change.  I didn't want to mess with it too much just before the show so I gave up but it is like he half gets what I'm asking him to do but isn't quite 100% sure yet.
It is amazing how fast the show is coming together at Caber.  Two days ago they were still mowing; today most of the portable stalls were up, most of the cross country fences were numbered, and everything was mowed!