If your horse keeps putting their tongue over the bit you may find it is a reaction to the bit giving too much tongue pressure. Discomfort in the mouth can be a reason for a horse to rearing.
Hi, its my friend she has taken on a loan and the owner has got bailing twain from one end of the bit to the other so its lying across the bit?, ive never herd of this before?, bt all my friend has been told is that the horse had a previous rearing problem, and that this will stop her from getting her tounge over the bit? xxx
Would def steer away from bailer twine etc in the mouth!!!
The bit poppymoo has linked to is excellent. You need to allow more tongue room, you'll find she settles better then and isn't keen to get her tongue over the bit.