Understitching is a method of keeping bottom fabric from showing at the
fold. You open out the garment after the seam is stitched. Then fold
the seam allowance to the inside piece of fabric and stitch it to the
inside (or underside) fabric as close to the seam as possible without
stitching on the seam line. This holds the under fabric underneath and
keeps it from peeking out at the fold.
- posted 14 years ago