For those who prefer a quick visual, check out the video tutorial below (Note: in the video I've used contrast purple thread to help make it more visible):
There's also this step by step tutorial showing you how, please click on images for a closer look:
and insert your needle at the back side of either the top edge or bottom edge of your neck binding and come through the binding edge.
Sew a few stitches to secure into place, then make a loop with your thread.
You should now have a loop and the thread coming off the needle.
Hold loop open with your thumb and forefinger
grab the thread (with forefinger)
and pull it through the loop to chain stitch in place (check out video tutorial above to see motion)
Repeat threading through loop until your chain stitching is long enough to go around button,
then secure off by threading right through the loop to end.
Next sew into place at opposite binding edge to create your button loop. Neaten off on inside of garment.
Now you have one lovely thread button loop! Happy sewing friends x