here's my method:
I hand whip scraps together.
I use a slip knot for a knot, go down left hand batting, up immediately next to stitch, needle thru the loop, pull tight.
You are up on the left, sewing about 1/2"-3/8" from the edge. stitch down in between the 2 battings, up on the right batting, down in between, up on the left batting. always up through the batting & down in the seam. When you pull it tight, it butts, no lumping, the stitches inbetween keep it from bunching. stiches are about 3 to an inch. goes really fast.