From the British show The Avengers Emma Peel (Diana Rigg) and John Steed (Patrick Macnee) popularized the genre of spy-fi. With elements of undercover spy missions and science fiction, the series was extremely successful.
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.