Id do lots of transitions. And start in a roundpen. I always walk and trot my horse both directions before asking for the canter and i give them lots of room to be stupid, kick up their heels, get whatever stupid out, and then bring them down, catch their breath and then ask again and every time he gets rushy just bring him back down to a trot or walk wait till hes relaxed and then ask for the canter again
Hello Emily, I think that you need to completely relearn your horse to lunge. I don't know where you are lunging him but to learn it's always better to be in a round pen. Use your voice because verbal commands are fundamental.If your horse won't stay in circle around you, don't hesitate to use the whip to guide your horse by showing him the way and gently taping him on the shoulder if he's not answering to make him go back to the circle.
By using the whip correctly you should be able to fix the fact that he is no staying in circle. Once your horse is comfortable on the circle you can work on a larger place.
Also, if he's charging increase the lenght of the circle and allow him to burn of energy, still keeping him away using your whip for your safety. Really often horses like to rush and charge when lunging don't worry most of the time they soon calm down and go back to work. Try to keep him busy while lunging, make a lot of upwards and downwards transitions and talk to him. Don't forget that your horse is supposed to be completely obedient if this lunge work become dangerous don't hesitate to be supervised by a monitor :)
Good luck !
When he pulls against the rope give him a tank toward to. This pulls his head toward you and if he pulls it back out yank again. As for rushing try to have him walk while lunging only then ask him to trot then lope. Don't just go straight into the lope. This will slow him down.