I am making 10 flannel charity quilts for David's house. I have used flannel before, and it does stretch a bit. I use a longer stitch and a bit looser tension to prevent puckering. I iron without sizing, I don't like using chemicals for infants and young children quilts, just a quirk for me. Do use thin batting, or even a layer of flannel as batting. It folds nice, and is so cuddly. I do not use 1/2 inch seam allowance as it creates too much bulk.