Bit sliding, need advice!!

[You Wont Forget Me]

My horses bit seems to slide out the right of his mouth meaning it is tight against his left side of his mouth so when i try to turn right esp when cantering he wont turn right and its because the bit is tight against his left side because the bit is sliding! I have seen it on a few other horses bar mine and what to know Why is this happening? What can stop it??

 

[StormyMoments]

put some bit rings on - http://www.robinsonsequestrian.com/saddles-tack/briddlework/bridle-accessories/bit-rings.html

or buy a full cheek snaffle

and it happens because the horse isnt following the direction you are turning make sure your bit fits properly too it will do this if it is too big