What kind of batting are you using? The spray doesn't work well with poly batting. If I have room, I generally tape down my backing. Lay the batting on top of it to center it. Then I fold it back 1/2 way and spray a section of batting, smooth it out, spray the next section. I spray in a grid fashion about 6" apart. When done with that, I lay the top out, fold it back as I do the back, spray the batting, smooth the fabric over it. I think crawling over it would not be good.