Training my young gelding. While lunging or in a round pen he walks and trots well and understands commands to slow down. However, his canter is always super strung out and wayyy too fast. He tucks his tail in a turns his head outward like he is trying to escape from something. He doesn't and will not slow down, he just runs until I am afraid he will hurt himself so I ask him to stop...He does this regardless of whether or not I have a whip in my hand. I have not cantered on his back yet.
What is the best way to teach him that he doesn't need to run as fast as he can and to have a calm, collected, driven canter that isn't all sprawled out and panicked??