DressageArena.org

my horse had the same problem in the past. Take a surcingle, or a english saddle and use side reins and hook them to a low clip on the surcingle or the girth buckles and then to the bit. The first week make them so loose that there is not/barely any connection with the bit (you have to be very careful…horses can be claustrophobic, this could lead to rearing if done un-properly!) then the next week tighten each side one hole and so on (slowly) until she is used to the contact with the bit.

Have you tried a martingale for /training/? It might help.
Try dover saddlery .com They have nice martingales. I’m a hunter/jumper and don’t use martingales, so if you have a tack shop near you stop by and see if they have one there. Horses are mostly always trained to lower their head to a set position when the rider gently moves the hands back and forth-gently tugging on the horses mouth and opposite times. Try google to see what sites have a training method for this. ‘training a horse to set it’s head.’

Enjoy

training and practice