After much deliberating, I decided to do a dry run of my cup after all. I had decided I wanted to try the punch fold and the seven fold. I tried them both, with similar results- I couldn't get the cup in, but the little I did HURT really, really bad. It was, of course, accompanied by intense cramping. I was fairly relaxed, but I felt like I'd just shoved a coke bottle up there. I tried to slide my finger up the side to make sure it was positioned right, but I couldn't get it up.
I finally pulled it out (and it was a little bloody) and tried the C fold and that actually went in okay and opened up fine, but I could NOT twist it at all no matter what I tried. And the cramping was still pretty intense. I tried to leave it in for a few minutes to see if it subsided, but I couldn't take it and took it out and gave up, already spotting pretty heavily.