Kiting is a concept in exploiting game AI that involves keeping the enemies at a comfortable distance behind you whilst constantly moving.
You will recieve no damage as they mostly rely on melee combat, whilst you mostly rely on ranged combat.
If you were to look at it from a birds-eye perspective, the string of enemies behind you would look like you're flying a kite, ergo, kiting.
The same concept can be applied to the flesh pound's mechanics: slowly damaging it whilst keeping a safe distance and controlling his other mechanics such as the rage timer and rage damage-within-two-seconds.