To prevent those points from unraveling and stretching out of shape, you need to secure them with a back stitch or lock stitch. Backstitching is done by sewing backward and forward at the beginning and end of a seam, on top of the seam stitches, to prevent the stitching from coming undone.

What is the purpose of a back stitch?

In hand sewing, it is a utility stitch which strongly and permanently attaches two pieces of fabric. The small stitches done back-and-forth makes the back stitch the strongest stitch among the basic stitches. Hence it can be used to sew strong seams by hand, without a sewing machine.

Do you need to back stitch?

You can backstitch when stay stitching, but it may not be necessary because these stay stitches will be caught in the seam allowance and they are unlikely to unravel. These stitches are also frequently caught in another seam, which will also prevent these stitches from unravelling.