trotting strait to galloping!

So my ex trainer had an ex race horse thoroughbred and on her bad lead way would gallop hard core it you lean foward or if you lift your but off the saddle so sit DEEP and kind of pull back on the reins when her head goes foward pull back a bit put your feet foward like how a pro reiing horse will stop on the cues train your horse to slow down with these cues try to keep your legs off her and sit deep its kind of hard to explain with out really seeing you ride but I hope I helped a bit :)