I have a 14'3hh irish cob!basically he won't canter in the school!hes good as gold in trot walk&jump but just won't go into canter!unless he someone meets him in the corner with a lunging crop or unless he's getting lunged!his tacks all fine&fitting!&his back&everything else is fine as he's recently been checked!my instructor says he's just lazy but I don't know what to do!when he's with other horses in the arena he will canter perfectly!but if he's on his own he won't!hes will gallop&canter amazingly in the field just not in the arena!so my question is how do I get him to go into canter?!i use a crop&he doesn't respond to spurs!but how do I get him to canter when asked??