My horse is pretty disrespectful on the lunge line. I'll ask him to trot (with my voice, and I crack the lunge whip on the ground if he's being lazy, which he ALWAYS is at the lope) and he'll throw his head in the air, sometimes pins his ears, and then trots. When I ask him to lope, however, he pins his ears and bucks. Sometimes he even bucks right towards me.
He NEVER does this under saddle. I know it's not a pain issue, he's just being disrespectful.
Any tips on what to do?