A frequent scenario that occurs while fly fishing: you are retrieving the fly line while presenting the fly. The fish takes the fly and the fly fisher, tight to the fish, continues to fight the fish, with coils of line at their feet or on the apron of deck of a vessel (float tube, pontoon boat or drift boat, etc.), by stripping the line/fish inward.

This is not a huge problem if the fish is smaller and the fisher can strip it inward to the net/hand. But, if the fish are likely bigger, my advice is to get the fish on the reel/drag. Do not continue to strip in lengths of line while pinching the line to the cork. I know this is common, I do it also for fish up to 18-20 inches. 

A second problem: the coils may or may not be a problem of tangling as they lay below the reel. I recently purchased a Rio Aqua Lux Intermediate line for stillwater fishing. My previous, older Intermediate coiled badly in cold weather and frequently had multiple knotted, messes tangled on my apron.

When a larger than usual fish took line, the knots jetted upward toward the stripping guide. The knots jammed there, or if they made it through the stripping guide, they definitely jammed against the more fragile second guide. Fish were lost or damage occurred. The new Rio Aqua Lux line never tangled once during days of fishing and thousands of strips. Sure there were a couple simple slips knots, but not the sticky, coiled tangled messes that use to beset my old Intermediate line. 

My suggestion is buy quality lines that are less prone to tangles/coils and when that uncoiled line slips up through the guides, as a bigger fish takes line, get that fish onto the reel. Even if you pinch tight to the cork at the first signs of a hook up, reel the loose line onto the reel in order to get tight to the fish.