Gently bend a piece of purple licorice in half, pinching the two ends. (Don't cut the licorice)
Lower the licorice into the bottom of a cellophane bag, leaving about 1" of empty space on either side of the ends for the next colours. Try to insert the licorice so the ends are behind the folds in the cellophane bag.
Lower in a piece of blue licorice and shape it evenly so it arches over the purple piece of licorice.
Add the green, yellow, orange and red pieces of licorice, shaping the rainbow as you go.
Add gold coins over the rainbow so they are in front of the folds in the cellophane bag.
Pinch the bag closed and stretch a tiny elastic over the cellophane bag to hold it closed.
Cut a piece of ribbon and tie it in a bow around the tiny elastic. If the elastic is still visible after you tie the ribbon, snip the elastic with a pair of scissors and pull it out.
Notes
One bag of Twizzlers will make 5 rainbow treat bags.