Sandwiching is a tricky task. I try to do mine on my king sized bed, but sometimes the quilt is too big and requires the floor. I use spray basting and have found that sometimes I pull a bit too much on the batting when smoothing it out. If it stretches out when I smooth it out, then it will retract after sticking to backing and cause wrinkles on the backing fabric. The trick is to just let it "fall" over the backing all while smoothing at the same time....LOL. You may need to pull it up and let the backing retract a bit and then gently put back into place. Clear as mud, right?