Hi BrookeC.
well.....I can tell you that there is a device out there called......"INSTEAD". It sort of inserts as a diaphram.....but keep the "liquid" from escaping.
I know...probably TMI....but what the hell.....like this site hasn't had too much TMI ?? go figure
anyways....this product (which you can buy at any walgreens) serves to keep Aunt Flo at the back door. I've used it several times.....with success..
Good Luck !
Rainy