Oh boy, looks like we've run into a problem.
In the last few lessons Aslan has been very "anxious" in his behavior. As Jonathan Field has eloquently put it, "The feet never lie." A squirmy horse is an anxious horse, even if he is not blowing up and flailing around like crazy. This is how it goes with the introverted Aslan, who tends to only subtly show anxiety. It can be so hard to notice as he doesn't necessarily explode the second he becomes uncomfortable. He is very good at holding it all in until he becomes overwhelmed.
Take the balloon exercise as an example of how good much of an introvert he is. I tied 4 helium filled balloons to him. Immediately his head was up a bit, ears were back in the listening position, whites showing or in the least, eyebrows are peaked in anxiety. But he stood dead still. He looked at me with a worried expression but would drop his head down, since I often ask him to do that when we do desensitizing. It's like he's "forcing himself" to stand there and drop is head, but he is *NOT* relaxed. If I ask him to move, the feet don't lie. He may scoot sideways or walk quickly, looking back at the balloons which are now "chasing him". He doesn't panic, pull or drag me, but certainly can if he gets too bothered.
In another incident, he was even trotting around me like an Arab and snorting and still wouldn't try to drag me. But if I'm on his back, it's like I'm not there, so his fear becomes magnified.
We have a LOT more desensitizing to do. Besides being anxious, we've even had one day where he all but refused to go to the back of the arena because he could hear voices coming from the alley back there, through the walls. (It's been months since he did this!) He became very upset and scared, which interrupted our lesson and I had to spend 10 minutes doing "random" exercises to get his attention back and moving closer and closer to the back. It also made me wary of giving treats because if he were to spook while taking one, I would get thrown off balance too easily.
Clearly the balance between sensitized and desensitized has been tipped too far. It's amazing how it swings so far one way then the other way! It is going to be a long time before it sits horizontal for us.