mofire

Got this from another guy on another forum.

It's easy. You wick ten or so rounds of FastFlite or bowstring material around the tips of two of your fingers. Then tie the free ends together.

Now you have a "string ring"!

Put it behind the bowstring so that it stretches across the middle of the ring (halves it), and the knot where you tied the ends is near the bowstring. Fold the ring toward you, so that it forms the "D" on the bowstring. At this moment, it didn't have to be at its proper position. Anywhere on the bowstring would do. But now you'll have to put the "D" on the outside of the nocking point.

Now is the time for some fine fingerplay. You'll have to serve the "D" from the upper to the lower point where the string ring went around the bowstring. Make sure the lower fold goes below the lower nocking point!

That would be it.