To finish off a fly, the materials (usually hackle fibers) are swept back away from the eye of the fly, exposing and area that becomes the thread head. The fingers (usually thumb, forefinger and middle finger or the less efficient thumb and forefinger ) are used to form a triangle or pinch of sorts, which gathers and sweeps the fibers to the rear. It often takes a few attempts to gather all the fibers and sweep them back with the off-bobbin hand.
SwittersB & Exploring 
I see you have flash around the body. What kind is that?
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It is medium size tinsel (one side gold, one side silver). It comes in a few widths. It was quite common say twenty years ago. It was common on steelhead flies as a flash component. It was less used on trout patterns; used predominantly on streamer patterns. Today, copper wire ribbing is more prevalent for trout patterns.
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