In short: when the bit goes in his mouth, he sticks his tongue out the left side of his mouth. There is an ever so slight crossing of the jaw that accompanies it. Mostly, it's just the tongue, pushing out the gap in his teeth.
Not much! And not badly. But it's definitely happening. Degree is the same whether there's active contact with the bit or whether the bit is just sitting there.
I don't have good feedback on whether it happens when he's really through and engaged. I know it happens when there's some contact but not engagement, though.
Evidence. This is about as bad as it gets.
I am hoping that it's because the bit is too thick in his mouth. I have plans to get him a thinner bit: either this Sunday at Everything Equine, or online from Smartpak if I can't make it there/can't find what I want.
Any other thoughts?