I've seen techniques for this but have allways been stubborn and crammed the little bunches of fabric (yes I know there is a technical term that has probably been reduced to an acronym under the foot.
I was at walmart today looking for thread. I stumbled across this stuff in a spray can used for quilting. I am an artist and it looked exactly like spray mount. Basically adhesive in a can. Figured I'd try that since I already had some.
Well short story shorter. Block your edge with a piece of paper. Spray both edges that you intend to 'inject' together' (sorry I kept wondering if I needed to sell my sewing machine for a thread injector. allow to dry and then you can stick them together. no ill effects and I just sew... injected, hmmm about two yards worth of scrap without one side being longer than the other.