We had two breakthroughs:
1. I got on him without walking him around the ring to look at everything first.
2. I carried and used a whip!
After about 5 minutes, I got sick of not being able to get him to move off my leg well enough, so I got off, put him on crossties, ran out to my car, got a whip, and got back on. I wasn't sure how he'd react to the whip--my last fresh OTTB reacted strongly to the sound of a whip being used on another horse--but he was fine.
Contact is tricky, as is not going around with his head up and his neck stiff, but he's surprisingly good about other things. We did a little leg yielding, which was actually pretty decent. Did a few turns on the forehand, which were good. We trotted circles and figure eights, and we were able to change nicely! Without totally falling in and being gross!! Even changing to the right! It was kind of funny, actually, because we'd change to the right, he'd do it nicely, and then he'd be like "omg, we're going right, I'm bad to the right" and promptly counterbend himself and fall in through the corner. Silly boy!
He really seems to be coming along well. A fabulous dressage trainer is coming up from Florida in about a week for a clinic, and I'm hoping he can come to my barn so I can ride Riv with him. Or just have *him* ride Riv!