I sure someone has already thought of this one but I couldn't find this in any of my serger books. To use this technique you must have fabric with an attractive wrong side and you must have flatlocked the seams. I wanted to show the wrong side on the edge finishes of fleece PJ's I was making. I used pearl crown rayon thread in the upper looper and finished the edge with the wrong side up. Then I turned over the wrong side to the right side and stitched down along the top of the decorative serged edge. I did this for all edges: hems, casings and neck. The picture shows the casing. It was extremely easy and made the inside of the garment extremely comfortable as no edges are on inside. The only potential problem with this is the ladder stich on the seam wrong side shows. This could have been avoided if I used matching thread in the needle. However, these were PJ's and the contrast didn't bother me. It is also pictured in the photo.