I tried to get riding video over the weekend, but it wasn't possible. (I'm intending to try again during my Wednesday riding lesson, if I can't manage it before then.) In the mean time, I've been attempting to take the advice you fine folk have offered me here: I went up to the riding school this morning to do some groundwork with Dubbin. Hey, guess what. He's figured out a new form of brattishness. I know that horses are normally poop factories, but Dubby's decided that producing a steaming pile every time he's tied up to the hitching rail is a great way to make a statement. *sigh*
...him galloping around the pen in random circles whenever he saw me so much as move the lunge whip an inch to the left while it dragged on the ground behind me. Ugh, what a pain. I don't think he was at all scared of it. He just wanted to make his uncooperative refusal very obvious.
Eventually I managed to get him to walk around the pen quietly and calmly for a couple of laps without stopping, then the same at a trot. Then we did it in the other direction. OK, I've decided that for the moment I'm gonna call that a success. It is, at least, a start, right?
A few things. I think you are taking every micro-behavior by Dubbin rather personally. First, when horses are stressed out, they poop more. It happens to people too. When my horse sees the trailer, he poops like crazy. It's not personal-- it's his autonomic nervous system! Please don't think he's pooping to make you angry. How could a horse possibly realize that given how many times they poop in a day?
Think of the excessive pooping as a sign that you need to make him more comfortable and at-ease with working.
As for the groundwork... you make it sound as if there was (1) a lot of tension, and (2) not a lot of previous training with this. Even though I lunge my boy regularly, every single time I will desensitize him with the lunge whip by rubbing it aaaaaalll over while smiling and telling him what a good boy he is. If I am working with him (and become frustrated because he's not listening), run to the barn, get it and rush back in a hurry all of the sudden he is nostrils flared and flinching-- so I desensitize again. Not because I have ever, EVER struck him, but simply because he knows a frustrated or anxious person waving a stick when he sees one! That's my fault. It's my job to take a breath, calm down and smile and apologize. Even if they know the whip isn't necessarily bad, if the person controlling it is behaving erratically, stressed or angry-- it can mean something else and therefore make him wanna run like all get-out!
Finally, do you have basic verbal and postural commands set with your horse? For example, when I lunge: an upward transition is spoken with my pitch going higher, a downward transition is spoken with my pitch becoming lower. Every command is preceded with an "and" to prepare for the cue; "and waaalk. and trot!" If verbal commands don't work, cluck means trot, kiss means canter.
My body follows my horse. If my body falls behind my horse, he slows; if it turns ahead of him, he picks up the pace. If I slump or crouch down, he knows he'd better stop.
I hope this helps. Take a deep breath, put on a
(even if you don't feel it) and try to stay positive! Reading up on the subject or having a new plan of action often empowers me to stay happy and focused.