I'll make a confession: I didn't really understand my anatomy until now. I thought the cervix was at the END/TOP of the vagina. Today, the first day of my period, I felt around in there more thoroughly, and took a look at some diagrams on google images, and sure enough, the cervix is more on the SIDE, with the uterus pitched at an angle. Everyone else here probably already knew that. I actually realized, feeling around, that I could feel both sides of the bottom of the uterus actually sticking out into the space of my vagina--significantly.
So this is the context of my problem: when I put in the cup, the only way I can get it to STAY popped open is if I push the whole cup past that ring of hard muscles near the entrance of my vagina. If part of the bottom of the cup is trapped between those muscles, the cup will compress slightly; it won't stay fully opened, which is obviously asking for trouble. So I always push it past, where the soft back wall of my vagina allows the cup to stay open. I try to tilt the opening of the cup toward the cervix, but here is the problem: there just isn't quite enough room for the cup to be past the ring of muscles AND accomodate the cervix. Instead, what happens is I can feel with my finger that one side of the rim is touching the lower edge of the cervix--which means that the very edge of the cervix is peeking outside the cup.
I'm wondering if this is the source of my occasional leaking... maybe it's the case that most of the time the blood goes into the cup, since most of the cervix IS inside the cup, but if the cup changes suction or whatever and shifts even a little bit higher, it goes past my cervix, and that's when I get a gush of blood? Anyone have a similar experience, or opinions about my "theory"? And second question: would anyone advise getting a shorter cup that's still wide enough to not go past my cervix? I hate buying new ones, but it's better than going back to pads/tampons.
Thanks in advance, and sorry for the length.