Been a couple of years now since I got an IUD and haven’t needed a cup. But I used one for a few years and had a great run (wish I’d been brave enough to use them before). Sadly they were some no name brand I got on special overseas so couldn’t tell you what to get. They sent a medium and large size, the medium was supposed to be for women my size who hadn’t had vaginal births but it leaked so I tried the large and that fit me just right. Though it took a few tries to work out how to fold and insert smoothly. Also my very first time I pulled it out without releasing the seal… do not, under any circumstance, do that.

But yeah it’s hard to tell without just trying one first, to work out the size and shape of your vagina. The first may not be the best fit and you may have to wear the cost of trying again. Once you find one that works though, it’s SO awesome - cleaner undies, fresher cooch, much less anxiety around leakage.