I've been learning about cups for a while and when I went to college I decided a cup would be more compatible with my active lifestyle.
Eventually, I bought a small Lunette and attempted a dry run. It took me a while to finally insert the cup, but once I had, I felt a strange pinching feeling as the cup popped open. I assumed that it was because I was pretty sore from the numerous failed attempts at inserting the cup. But when I tried inserting the cup during my period, I felt the same pinching feeling. I'm not sure if I'm inserting the cup incorrectly, or if it hasn't popped open completely. That and I've also noticed the cup sitting pretty low inside me, so I think I maybe have to insert it a little higher for it to sit comfortably.