Has your ponyboy ever tried to bite down on his bit to avoid the action of the reins? Maybe he didn't want the tongue port getting pulled to the back of his throat, or maybe he's trying to protect his soft palate from curb action, or, if he's like me, sometimes he just likes to grab hold of the bit just to be naughty.
So what do you do? You could put your back into it and give the reins a giant yank, but that's just mean, and besides, you don't really want to dislocate your ponyboy's jaw. So, then what do you do?
Well, I was reading this story (not for everyone - it's a non-consent, forced pony play story), which describes a bit perfect for using on such ponies:
"...at the sides where it interacted with his teeth...the [bit] was contained in a rubber or plastic covered sleeves. The result was that his teeth...had no purchase on the bar that ran through the sheath."
In addition to having a U shaped tongue port attachment, the bit in the story also has coverings (or sleeves) so that if the pony decides to bite down on the bit, he still cannot stop the action of the bit; he cannot stop the U shaped port from rotating in his mouth. The whole concept of this bit is really cool to me.
As a pony, when I bite down on a rubber Pelham with bit port, I can usually stop (or at least slow) the port rotating when the curb reins are pulled. Although T can certainly crank on the reins, there is something diabolically hot about having me wear a bit that I can bite down on as hard as I want without having any effect whatsoever on the bit's action.
I think I like the idea of this bit for the same reason I like electrical play: I can attempt to resist as hard as I can, but with only slight pressure on the reins (or a simple push of a button with electrical play) the person at the other end of the reins can bring me to a screeching halt (or can have me in a puddle on the floor).
After reading about this bit, I set about trying to design one in my mind. I tried to figure out what I would need to modify an existing bit to add these sleeves to the mouthpiece. Of course, all of these plans were a complete waste of time because a quick visit to my favorite search engine revealed that such a bit already exists for bio-horses. It didn't surprise me (no piece of tack should come as a surprise to us tack loving equestrians), but it did make me feel quite silly for not knowing about such a bit beforehand.
Anyway, there are quite a few bits with rollers where a pony's teeth sit (these are different from bits with rollers at the center of the bit, which do not have the same effect of stopping a pony from getting purchase on the bit with his teeth). However, a second requirement of the bit was that it had to have curb action. If it were a snaffle, the mouthpiece would not rotate - though in a snaffle, the rollers would prevent a pony from effectively biting down on the bit to prevent it from being pulled back further in his mouth.
I decided on a Pelham (because why choose between a snaffle or a curb) with a jointed mouthpiece and three copper "cherry" rollers on each side of the joint (the bit is pictured in the photo on the right). Cherry rollers are slightly raised rollers, versus flat rollers, which would be flush with the rest of the mouthpiece (either style should work, it's just that I came across one with cherry rollers first).
Also, if you don't want your pony's teeth coming in direct contact with metal, you can wrap the rollers in vetwrap. However, if you want to keep the effectiveness of the rollers, you would need to wrap each one individually with a small width of vetwrap.
After wearing the bit a few times, I'm quite happy with how little grip I can get on the mouthpiece. I have no way to prevent or slow the curb action no matter how hard I tried to bite down. I also gave the bit a try with a rubber tongue port attached, and I can definitely vouch for its efficacy.
It's kinda funny (well it would be if I wasn't the pony): I didn't actually realize how much I do bite down and reduce the action of the tongue port until I used this bit. I'll tell you, I thought the tongue port/curb bit combo was effective, but it's so much more effective when I couldn't fight it by biting down. The only disadvantage is that the copper rollers tend to promote salivation, so next time I'll try to get one with stainless rollers.
If you're interested in a bit like this, they are actually available from several tack shops, but the price will vary depending on whether you get a snaffle, curb, or a fancier western style show bit, etc. However to get you started, here are a few places: