Here's the deal. Once we've done a warm up canter, he pretty much refuses to acknowledge that the trot gait exists from that point forward. I am trying to work on refining our trot-canter transitions. He's extremely willing to canter on the bit, but once I downshift to the trot, I can half halt, circle, leg yeild and serpentine my butt off and all he'll do is keep trying to jump back into the canter. He looks like he's doing little bucks every step. He comes above the bit and refuses to downshift into a soft forward trot. I've tried holding the contact steady and trying to flex the inside rein. I've also tried releasing the reins every few strides so he can't lean on them. Neither works. He simply has decided that trotting correctly is work and he's going to hold his breath until he turns blue. If I canter before he softens, he's won. If I drop to a walk, he's won. Luckily he's kind soul, but he's definitely thick in the head when he doesn't want to do something. He's really got my number this time. Thoughts?