I finally after about twenty tries got the Diva to pop open fully. This is definitely why I switched to Mooncup. It's amazing how much more the Diva scratches the vaginal entrance when I insert it than the Mooncup. Anyway, I wore it for about twenty minutes without problems or leaking. Suddenly? Air released and I felt around, and, sure enough, it lost the seal as it was trying to slide up and to the left like the mooncup does.
This is probably why I NEVER got a seal with the Diva, because after a time it tries to suck around my left-tilted cervix and, since it can't tilt due to its length, I lose the seal.
So, score one for the Mooncup, but I've found that I still have problems when the cup sucks far up and to the left. Not only is it hard to reach, it causes a LOT of cramps and discomfort. I guess what I'm asking is if anyone has any advice or techniques to keep it from sliding upward. It's hard enough to get either cup to seal, and on the rare occasion that either does, I lose the seal eventually due to my tilted cervix. I've mostly given up on the cup, and Instead made me sick (something to do with the materials), so barring my asking for a diaphragm at my next gyno visit (which I am actually planning on), I am pretty much switching to cloth pads at this point. But, if anyone has any advice that might help, I'd appreciate it. For a long time I wasn't getting either cup to open, and now that I can, I see that it's not the only problem.
Thank goodness I found cloth pads, because after trying cups for two years with limited success I was starting to get pretty frustrated.