A simple way to keep this skirt on and give it a finshed look is to add a drawstring waistband.
Mark where you want the drawstring to come through. Then cut a little slit in each place. (you can sew a buttonhole here if you prefer.)
(Turn inside out)
Fold down top of skirt to form casing for the string.Sew it all the way around. If using a machine a small zigzag stitch will again allow for stretch without popping the seam.
(Turn right side out)
Grab your string or ribbon or waht ever you want to use to tie your skirt.(i used the string from an old hoodie which just happened to match perfectly)
Attach a safety pin to one end of the string and thread it through one of the holes you cut earlier. Push through until it comes out the second hole.