This should probably go in training of the rider! Anyway, me and my mare are in the process of learning how to go on the bit at the mo but I find that when I start to work the inside rein as my instructor says then Kiras head comes up rather than 'in' (if thats the way to explain it) and also when I ask for a bit more impulsion through her body she speeds up and shortens up her stride(almost shuffling) rather swinging through from behind and stepping into the contact . Im not too good at explaining all this but any advise is much appreciated