I use some and love them! I just put together two pieces of leftover batting in between two pieces of flannel, and overcast the edges with my machine. I used a 10 cm circle (I used the circle in my birthing class book for how large your cervix needed to be before the baby comes out - LOL) to make my template. I just used leftover batting and flannel. They are super comfy, and work great (I leak like a sieve). I hated the store-bough washable kind that had a seam in them. Whoever decided that a seam on your nipple is a good thing, especially while nursing? They also wash great!
Oh, and to all of the men on the board, sorry if it's TMI.