This is just a very slight and simple practice that helps me get my horse’s mind right before a ride. My gelding can get amped up easily and extremely distracted, especially in a setting with other horses. If that is the case before you mount and you don’t have time or space to do the ground work you’d like, you can simply work on him lowering his head. I will stand to the left of my horse and gently rest my hand on his poll. I don’t put distinct pressure, but I let my hand be heavy. The moment he drops his head even a tiny bit, I keep my hand where it was in space, releasing the pressure on his poll.
I’ll do this until his head is well below his shoulders and he begins licking and chewing. Sometimes all I need is to get his attention and this works wonders in calming him down, getting him focused, and helping him feel secure in his situation. Not sure if that is something that would help your horse, but it’s helped mine over the years. Good luck!