I'm not a high elo player (don't play ranked), but that can be a useful method of reducing the amount of damage you take from camps. Functionally, you are kiting the monsters around within their leash range, in the same way an ADC kites enemy champions. The best way I've found to do this is use attack click and then just orb walk around the monsters. You want to make sure that you step far enough away that it causes the monsters attack animation to cancel (allowing you to avoid damage), but not to wander far enough away that the monsters start to soft leash (because that can really screw up your clear if you mess up). It isn't the most essential technique to learn, but the high level players do it so they can maximize their health during their clears. It can be very useful on weak early junglers who take a lot of damage/don't have much sustain, but most good jungle champs can get by without it.