If you pin your batting, backing and top as one and then iron, it will compact the batting and allow you a little more freedom in choosing a quilting pattern. In some cases, the scrim on the batting will sort of seal the layers together. To release the batting to then "poof", either spritz heavily with water or drop in the washing machine and dry. If you stitch in the ditch, be sure to use your walking foot.
Obviously, try a sampling first before an entire quilt.
Suz