I have used it on several grandkids' quilts without any problems. I used my regular Quilters Dream cotton batting and pin basted as usual. It really makes a cozy quilt. Didn't notice any stiffness at all. I have used Minky from LQS and Joanne's. I do FMQ on my DSM so can't answer about a long arm machine. It can be stretchy when cutting but has more stretch on one direction of the fabric than the other, can't remember which way now, but you can tell when you start working with it. Good luck, your grand baby will love it.