Using the hammer and nail, punch 1 hole in the bottle cap near the edge. Punch a 2nd hole directly opposite of the first, again near the edge.
Cut the stretch cord (or elastic) long enough to fit around your finger with a little extra left over for tying the ends together.
Thread the cord with the desired amount of beads.
Thread both ends of the cord (or elastic) through the holes in the top of the bottle cap. Tie off the ends of the cord (or elastic) together on the inside of the bottle cap. Make sure the cord (or elastic) loop fits your finger snugly so the ring won't fall off but not too tight that it cuts off your circulation. Untie and re-tie to make adjustments and then make a knot when the loop fits right.
Cut a circle from the scrap fabric approximately 3 1/2 inches in diameter. This is the optimal size for plastic bottle caps (from soda or water bottles). For caps off of glass bottles (beer and glass soda bottles), you'll want to cut a circle around 3 inches in diameter.
Hand sew a running stitch along the edge of the fabric circle.
Cinch the circle nearly closed, leaving just enough of an opening to fill the small "bag" you've created with the stuffing. Once you've stuffed the cushion, cinch it closed and tie off the thread.
Using the hot glue gun, squeeze hot glue into the bottle cap covering the knot you made on the inside. Place the sewn end of the cushion into the inside of the cap.
Hot glue trim around the edge of the cap if desired.