When I first got my cup back in... November or December, I never had a dry run. I figured I would just wait. I got pretty good at putting it in an taking it out after that first time. I even devised a pull and push method for when I didn't exactly insert it right, and it didn't quite open up, and that always works for getting it to 'pop' open inside. Last month I never got my period (stress I guess) but I attempted insertion once. I tried the 'pop' it, and that didn't work. I have heard around the internet, might be on here somewhere, that the vaginal canal sorta bunches up a little during a period? Would that explain why my "dry run" didn't quite work, since I wasn't actually bleeding? If that is the case, it might explain why some people have issues on their dry runs.