DIY Baby Changing Mat Tutorial: This is a fast and easy sewing project which makes a wonderful baby shower gift. You can use PUL or oilcloth to make the changing mat waterproof. Using either batting or flannel makes the mat nice and softly padded for little babies. Place an elastic loop about 1/4 of the way down the shorter side, so you can easily roll up the mat. This changing mat is a diaper bag essential!