Thread a handsewing needle with thread. Tie both ends of the thread in a
knot so you’re working with a doubled thread. In the demonstration, I’m
using embroidery thread and a big needle, so it’s easy to see. Stitches
will be smaller and less noticeable with regular sewing thread.
Working from right to left, take a small stitch in the seam and bring
the needle through to the right side of the fabric. Insert the needle
back into the starting point, slide it under the first stitch and bring
the needle through the right side, one stitch ahead of the previous
stitch. Repeat until you reach the end. There should be no space between
the stitches.
Here’s what it will look like on the opposite side. You’re essentially
sewing loops of thread around the two layers to hold them together. The
reverse side shows the loops of thread.
