I use felt because I make large wall hangings and it keeps it's shape -- no ruffling around the edges. You can iron it but because it's probably polyester you can't use a very hot iron. Experiment on a scrap with your iron. I have never had a problem with it. You could also use a layer of wool batting next to your top and on top of the felt to add dimension to the quilting. I've done that and been happy with the result.