You know when you have a costume piece that just won't stay exactly where you want it? For me, it's usually the placement of straps on scanties, which I like to position 'just-so' to minimize bulging and maximize a flattering line. Or stapless anything... bra, dress, something that keeps wanting to slip off the shoulder. Well not anymore!
You know that sticky silicone banding that is on the top of thigh-high stockings? It's also on the inside of some strapless bras and dresses. Well,
why not buy some and just sew it to the back of the item you want to have stay in place. It comes in black, white, nude, and some limited colours. It also comes in a crazy variety of widths so that you are sure to find the size that suits your project. And.... it's elastic! So no worries about needing stretch. You can get a limited selection of this miracle fix at most frabic stores, but I am buying mine online from Sew Sassy Fabrics.
In fact Sew Sassy Fabrics is amazing in general. Browse through their product offering and discover everything from bra-making supplies, to every variety of specialty elastics and stretch lace. There's even stretch lace with silicone backing, exactly the sort used on thigh-highs.