Cotton fabric, as much as you need.
Scissors, yarn, sewing machine. ( I am sure you can do it by hand if you want to)
Filler: I used pearl barley. That was on sale at the store. You can also use uncooked rice (not minute rice), wheat, feed corn, buckwheat hulls, beans, or flax seed.
Cut your fabric into the shape you want. I used a 9 inch quilting square as a guide.Sew the front/pattern sides together making sure to leave an opening so you can turn it right side out. I sewed twice around the edges just as a safety if a hole was ever torn. Fill 1/2 to 2/3 full with desired filler. ( I used a 16 oz bag of barley.)
Sew hole closed. Heat in the microwave for up to 3 minutes depending on the size. If you are worried about a fire, fill a mug with water and place in the microwave with the bag. Shake the bag well and check the heat before using it on a child.
While not in use keep it in the freezer as a cold bag.
If you are worried about germs, you can wrap it in a towel, or make a case for it. I am pretty practical so a towel works fine for me. Also, the microwave and freezer both disinfect the bag. The microwave will kill anything growing in/on it. So I think it is pretty sanitary.
PS In second grade I was given sew as a spelling bee word. I misspelled it. I am not sure which one was even given. Sew or so. "Sew" forgive me and my aweful spelling if there is ever any errors.PSS Don't forget to enter Rachel's Giveaway!