When I wash my fabric I always iron it with steam. I also keep a spray bottle of water just in case there's a stubborn wrinkle. I also use steam with my pieces though, but I don't iron back and forth I take my iron place it on the seam and steam. Haven't had much distortion. I like my seams set for when I'm sewing them together, they just seem to lay flatter and stay in the direction they need to be.