Not necessary to spray. I water it down 50-50 or even a little more water. Then it is thin enough to come out of the bottle easily. I just hold the bottle above the batt, squeeze and move quickly back and forth across the area in lines about 8 to 10 inches apart. Then I use my fingers to run over the glue just enough to smooth out the larger blobs. Smooth that section down and you're ready to go to the next section. I usually use the iron to dry it at least a little so it won't move when I move the quilt.