Valentine's coming up in a week, so I wanted to make something fun for Husband. Too bad I had to give it to him a bit early, to get these photos :)
You just need some scrap pieces of fabric. You could make one that's from the same fabric as your dress, or make it out of two different (but complimenting) fabrics.
(You can vary the widths/lengths as you want)
Now for the middle part:
(You don't necessarily need to iron it before sewing, but it helps to keep it straight.)
And then turn it seam inwards (you can use a stick to help you with that).
Iron it like in the photo above: with the seam closed, inwards and in the middle.
The seam-line is visible but the seam itself is inside the "tube".
(At this point, have the seam-line facing outwards)
(Remember to have the seam-line facing outwards so it won't show once you turn the loop out)
After sewing, turn the loop inside out so the elastic band and seam is on the inside of the loop.
(Now there middle-seam is tucked inside the loop and won't show)
Sew sew-on-snaps onto the ends of the elastic (you can wait with this part until you get to measure how long the elastic should be on him). I recommend zigzagging the ends onto the elastic so they won't start to unravel.