Not sure if this will work for you, and you don't have to share any secrets ha ha. My friend got a radio with some really, really upbeat music on it and let her horse run around to the music in the arena and he would step with the beat and ended up like jogging on the spot almost like a piaffe. After that she tried some in hand stuff like stood next to him and held his halter shed rock him back and forth . Sideways not shoulder to croup. And he would step up when she did so he was stepping side to side with the music. Now when she rides him to music she can get him to shorten or legthen stride according to music. Its pretty neat.
Tomorrows another day, and Im thirsty anyways, so bring on the rain.