Cut off the feet and the legs portion below the hole.
Hem the edges with a zig-zag stitch.
Sew in a couple of shirring stitches with elastic thread. To use elastic thread you wind the bobbin loosely by hand with the elastic thread and sew with the stitch setting on a 5. Use your normal thread on top.
I added a ribbon and heart decoration so it could be a special something to wear around Valentine's Day.