The following technique was taught by Roberta Carr at a class I attended at a Fabric Market in the 90's. I learned lots of 'good stuff' from 'Bobbie" as she was affectionately known.
This Ultra Skinny Couture Turned Fabric Cording (the best description I can come up with) is done with a needle and strong thread. It can be used for cording for Oriental Buttons, for loop closures, for couching on top of fabric, or even for stems and loops to create a wonderful lapel flower.....
1. Start with a BIAS cut strip - plenty wide for ease of handling - say at least 1 1/2" wide.
2. Set your sewing machine on a smaller than normal stitch length - like 1.5 - 2.0
3. Fold fabric right sides together, and underneath the presser foot so you can guide it just a needle width from the fold. You might even want to make use of your needle position.
4. Start stitching from one end - BUT, start a bit further from the fold than what you established in Step 3 above - as starting with a wider width, then narrowing to your established width within 1" or so of length will make getting the 'turn' started easier.
This is important: STRETCH that bias, pulling from the back and the front as much as possible!
5. Using a doubled strong thread - buttonhole or carpet thread - attached to a needle, and stitched through one layer of the wide end, feed the 'eye' end of the needle down through the tube. When it exits the end, keep pulling it and the fabric will turn!