What I'd really like to know though, is it true what I read in comments here that a menstrual cup is not supposed to form seal with the walls of the vagina (like they show on diagrams and explain in instructions), but the cervix instead? I'm really puzzled about that. For starters, based on what it feels like, my cervix could easily work its way INTO the cup, given an opportunity. Sometimes it feels flatter and wider, other times it's firmer, narrower and longer. And somehow neither the idea of the rim of the cup forming seal with my cervix inside of it or sitting right on it is appealing to me... Not to mention, the thought of the the cup creating suction directly with the cervix or having to break the seal off the cervix... I feel like I'd be more relaxed about that idea if the rim of the cup was seamless and it was VERY soft (which is not the case with the one I got, on both fronts).
Not to mention, I feel a bit cheated and misinformed. If the whole cervix touching the cup and forming a seal with it thing is true, then why the companies that make them, don't make it clear? They're producing them, for pete's sake, how come they don't know what happens when you put it in?