A Flat Felled Seam is a seam, which is created by sewing together fabric on the wrong side, and then cutting the seam allowances close to the seam, and then continuing by flipping the alternative seam over and turning the other seam allowances under and top stitching it over the prior clipped seam allowances. This type of seam is often used to reinforce seams on garments such as pajamas or to reduce bulk in a seam, another way the Flat Felled Stitch is used to create a decorative finish on a garment.