You know those little flaps of fabric that cover your jacket's zipper to stop heat loss via the zipper? Don't you hate it when they get caught in the zipper? I fattened those flaps up with thick string so that there'd be no extra fabric to get caught. I could have cut them off but then I'd have a line of cold running up my abdomen and sexy chest. Sad face :(
Step 1: Materials and tools
String, or similar (thick enough to take up almost all the space inside the flaps, long enough to fill both flaps)
wire (thin enough to be able to pull through the flap while being wound around the string, about 4 inches longer than the flaps)
Step 2: Get inside those flaps
using the seam ripper I opened both ends of each flap, then I bent the end of the wire back on itself to prevent it from snagging when I pushed it through the flap. I then proceeded to push the wire all the way through the flap.
Step 3: Pull that string through
Once the bent-over end of the wire is out the other side you wind it around the end of the string. Make sure the winding is pretty tight because you don't want it to lose the string halfway through. Also: trim off any excess string otherwise this "knot" wont fit through the flap. Also also: make sure that the cut end of the wire is now facing the other way. I.e: when you pull the wire back through the flap along with the string you don't want it to snag anything. Now you pull the wire through and in so doing pull the string into, and through, the flap.
Step 4: Tie off the end
once the string comes out the other side of the flap you can cut it off the wire and tie a knot in it to keep it from going back. You could also stitch it to the end of the flap but this worked out easier for me. If you choose my method then pull the knot very tight and trim off any excess string.