Easy to sew: It's just 4 rectangles. Measure shoulder to hem length, then girth at widest part (hips?) and divide by 4. Add seam allowance. Sew allowing for neckline, arm holes. No pattern needed. 1/2 hour, max!
Couching is simply sewing a heavy thread in place with a finer thread. Its a retro technique, too, that was originally done by hand, but it works beautifully by machine as well. I use a zigzag stitch to secure the heavy thread in place. And, if you have a cording foot— the foot guides the thread as you sew.