I don’t know how to do it with bobby pins, but you can stretch an elastic waist band and sew it to the inside of the bottom hem. Then you hand stitch the hem up every inch or so.
Or you can sew an A-line skirt (or just a narrow skirt) to the waist inside which is 2-3 inches shorted than the skirt. Then you attach the skirt hems, making the outside skirt bunch up as you sew.
I think I know exactly the one you’re talking about: Calivintage in a blue plaid dress? I’ve actually been doing that with safety pins for several years now. There’s a psuedo DIY instructions, I did here.
Basically, turn your dress inside out. Take some safety pins and pin the hem up at even increments. Turn your dress right side out, see how it hangs, and adjust. It’s temporary and I’ve never even had noticable marks left by my safety pins. The dress shape and fabric will affect how well it turns out.posted about 5 years ago