Agree...if the horse has been checked by a vet and nothing is wrong... Then time to get tough...
He has your number and is
disrespectful of you both on the ground, you wrote of in a different thread
, and now astride.
step up and meet his attitude with a larger one of "not putting up with this anymore" this horses antics are only going to escalate...not fun and yes, dangerous.
A different mindset from you would be a place to start.
Positive, we are going to do this today, then do it...
If the horse steps out of line...ask again stronger with confidence...if he again tries to disrespect..nail him and mean it!
Give the animal a chance to do it right, if he does...fantastic.
If he doesn't he pay the consequence. You are being tested and failing.
It shows in/by his attitude with you.
When you decide enough is enough just be prepared for some strange reactions...he is not
expecting you to do anything but accept his bad behavior/manners & disrespect, so any reaction or push-back is foreign and going to get some sort of "Wow!!" response...be prepared!