What bits do to horses when you pull on their mouth

What bits do to horses when you pull on their mouth.  Do you know what’s happening inside the mouth of your horse? Not sure which bit is best for both you and your horse?  Here is a great video on what goes on inside the mouth of a horse depending on what bit you are using and what you are doing with your hands.  Some great info here and something to think about the next time you saddle up.