Clearing line quickly after hooking a giant tarpon can sometimes happen before you know it. These big beasts once hooked can clear your excess stripping line before you can blink.
After you set the hook on a tarpon, applying drag with your stripping hand by gripping fly line tightly helps to keep the line slack free and helps you to stay tight to the fish so the odds of a hook pull are less.
During this time frame lots can go wrong. The stripped line from the deck is being cleared up through the guides to the reel. It's your job to try to separate your line hand and your rod hand so your line that's being cleared doesn't jump up around your reel or butt section of your rod. If this happens, game over!