Long-time lurker here. I used and loved a Keeper Moon Cup size B for many years until I had to get rid of it as part of diagnosing repeated yeast infections. (Result: not the menstrual cup, but the condom brand. My vagina apparently hates Durex. The more you know...) Anyway, now that that experiment is over, I decided to get a new cup. Since I have heavy enough flow that I would overtop the Moon Cup in two hours at the start of my periods, I thought I would get a cup with a bit more capacity, and I so I bought a large Fleurcup. Never had children, cervix height varies from period to period, etc.
I never got my Moon Cup to rotate after insertion, but I could tell when it was properly open by running my finger around the outside of it. Same issue with the Fleurcup, except I can't get it to fully open... ever. I am not really sure what the problem is here. I have tried a couple different folds but I end up with the same result - a third of the cup is still indented in at the front. After exploring a little I'm starting to suspect that my pubic bone is keeping it from opening fully, since the indented bit is always in the front, pushing up against the back of my pubic bone. I never had this problem with the Moon Cup. I ignorantly hoped that this was just the way the Fleurcup sits, but the resultant gorefest in my underwear confirmed that the cup definitely isn't sealed properly.
Any recommendations? Is the cup simply too big for me?