A bit should fit your horse’s mouth so that the mouthpiece extends approximately 1/4 inch (0.6 cm) beyond the horse’s lips on either side, but not so tight that the horse might be pinched by any movable cheek pieces. You also don’t want a great length of bit hanging out of the horse’s mouth. The different parts of the mouthpieces on bits are made to sit on specific areas of the mouth. So for the bit to be effective, the bit needs to contact those areas properly. You also don’t want the bit pulling through the horse’s mouth when you pull on a rein.
( baldmonkey a frothy foul-smelling vaginal discharge, Tue 30 Jun 2009, 23:30, archived)

I'm that kid from Equus,
so you don't want to tell me what I should or shouldn't do to a horse.
( Master Of Turnips. Only gays and morons believe in ghosts., Tue 30 Jun 2009, 23:31, archived)