There are so many nuances that that can be used to enhance your experience when training your horse. Training without a horse is one of them.
When learning to longe a horse, it is a good idea to take away the horse.
If you practice coiling and uncoiling the longe line, with it attached to the fence, you will become more coordinated.
Attach your longe line to the fence. The fence is the new horse. Walk out to the end of the longe line. Do not pull on the fence, as that would be pulling on your horse. Do not allow the longe line to drag on the ground, because if it were your real horse, he may get hung up in the line.
Next, work on coiling up the line and walking toward the fence. Be sure you do not “over walk the line” meaning, you are walking forward and the longe line is dragging on the ground because you are not coiling at the same speed you are walking. Do not pull on the fence; this would be pulling on your horse.
Practice this until comfortable with both right and left hands.
Place a pole or similar object out in the arena to represent the horse.
Now you can comfortably practice using the whip. You must be coordinated using a whip in both right and left hands. Practice your aim with the whip, by aiming at a specific place on the pole. You don’t want to swing your whip toward your horse and accidentally hit him. If you become coordinated and accurate, you will be able to use your whip and not put the horse through your learning experience!
Be sure that you are aiming the whip at the correct place.
You should aim behind the horse, not the horses face or shoulder. Tap the ground and say walk, for walk, while practicing your hand placement holding an invisible longe line. I say invisible because you are only pretending you have a longe line. You will go through the motions as if you are really holding one. Work up to the jog, trot, and finally the lope/canter cues.