I have played with your pattern and have made about 6 of these. I wasn't doing very well using a zipper, (it just looked funky) so I ended up making these into snap bags. To do this, I extend the outside materials 2 inches on each side, turn the material to make a sleeve to place the cut tape measure. Works out well. Sometimes I put lace on the panties and sometimes I just put a small bow. Having fun making them. Will make some for my grand daughter's teachers for Christmas. Thanks for sharing your idea.