Your horse is trying to boss you around. Instead of YOU telling him what you want him to do, HE’S telling you what he wants to do. You have to be the aggressor.
I watch RFD-TV and there is this show called DownUnder Horsemanship with Clinton Anderson. I have learned so much from the show on how to add more to my experience of handling horses.
Anyway, on one particular show, there was this horse who had the same attitude of yours. Clinton Anderson used what is called a Handy Stick. He also said that you don’t want to use a whip, if you do you’re back to square one.
When using a device like the handy stick for lunging, step forward, hit the horse just between his ear and bridle path (where the top of the halter is on the head) for him to go in the direction you want him to go. As soon as you got him going either in the left or right direction, keep him going in that direction.
If you want him to change directions, change hands for lead rope and stick, so that if you have him in the direction of going right and you want him to go left, you once again be the aggressor step forward and with the lead rope in the right hand take your stick in your left hand and hit him in the same spot you used to get him started (Between behind the ear and bridle path). Do this every time you want him to start from standing position or changing direction.
It might take a few lunges around the arena but if you do this every time you lunge him, he’ll stop telling you what to do and let you tell him what you want him to do.