I have an Arabian who is a lovely horse (go ahead and sigh and shake your head, we Arabian owners are used to it ), but really he is a great little guy. I am currently conditioning him for some Limited Distance rides (25 milers) and he's doing well.
He came from a farm as a 'park and pleasure' horse (all that high stepping knee action). He rode in a half cheek jointed bit, so I put him in a regular snaffle when he arrived. He seemed fine in it, but would tongue it constantly. And no he doesnt' put his tongue over the bit, but hangs it out to the side or folds it up behind the bit and hangs the rest to the side...it's rather humerous to watch him in full action, but it freaks other people out. I will also add that I am uninterested in putting a caveson on him. This doesn't bother me in the slightest, but for safety sake and for his comfort I'm trying to figure out if it's bothering him...
He mainly does this when we are standing. He will occasionally do it when riding along, but he never pulls on my hands or tosses his head up. And most of the time he responds nicely to the bit-his worst part is backing, but where he came from they didn't do a lot of that under saddle, so he is willing, but learning how to go about it.
He is currently riding in a Myler comfort snaffle, 3 ring combo that looks like this on him and this is what he does:
This is not an overly thick bit and it lays nicely in his mouth. He does not like bits touching his teeth and whenever I take it out (did it at the farm too), he sticks his head way up, sets it in his teeth and then drops it at me. I've tried getting him to open up and let me take it, but it seems they let him do it at the farm too, so....it's taking some work to get him to stop. He will put his head down to poll pressure any time I ask, except when he knows I'm taking the bridle off.
Here is the bit Myler 3-Ring Combo w/Sweet Iron Comfort Snaffle - Adams Horse and Pet Supply , it's supposed to provide more tongue relief than a regular bit which I thought would help. He did seem to be more quiet when we started using it, but now he tongues it too. I also use it on the last ring which allows for moderate leverage, but he doesn't normally require a whole lot of rein.