GENTLY stretching and taping down the backing fabric really helps keep it from puckering. I lay batting on top, smooth out, fold back about half and spray the backing lightly. Point the nozzle toward the fold to minimize overspray. Hand press batt back down, smooth out, and do the same for the other half. Repeat for quilt top. I still use pins, especially around the outside edges....just insurance that the sandwich doesn't shift. If the quilt is larger than your table, use extra large binder clips to hold backing to the table surface and sandwich in sections. Look for a how-to video on YouTube.