My 13.2 Welsh x Cob mare sometimes (not always) doesn't go into canter so I use the whip on her hard enough so she actually feels something, but not so hard I am whipping the cr*p out of her! This makes her do pretty big bucks, head down, back end up! I do have experience with bucking horses so I stay on but it makes me hesitant to use the whip on her meaning she sometimes gets away with no canter which I know is bad! However sometimes she canter perfectly and is a very good girl cantering on a hack, so this makes me think that nothing is wrong with her back, although I may be wrong. She has had her saddle checked by a saddler and it fits perfectly so I cannot think why she is bucking. Does anyone know why she may be bucking and how I could possibly stop it? Thanks in advance.