I had nearly a 1/2 inch cut in my backing fabric on my first quilt. After thinking long and hard about what to do I took a small piece of matching fabric (just slightly larger than the hole) and ironed on some Lite Steam-A-Seam2 on one side, took the backing off of it (it's double sided sticky) and then carefully poked it through the hole, lined it up just right and then ironed it in place so that it was now sticking to the batting. Then I took another piece of the fusible web and placed it on top of the little patch and was able to make it stick with just pressure. Then I pulled off the backing so that it was sticky now on top and brought the top fabric over the little patch inside and pulled the edges together before gently ironing it all together. Hope this all makes sense! So in a nutshell, the "patch" was ironed to the batting as well as the top fabric of the quilt. It wasn't going anywhere! I was so pleased at how it all came together. Once I was sure it was cooled off and dry I did use a little fray-check just to make sure it would stay secure and not ravel. Now because this did happen to be on the back of the quilt I decided to go ahead and put my label over it...not that it looked so bad anymore but because I just wanted to make sure it would hold up to washings and the like since I was giving the quilt to someone that might be a little rough with it.
Good luck!