Question About Cup Shape

Hi all,
First, thank you to everyone who helped me choose my first cup. I have used the Si-bell for 2 and a half cycles (the half being five days of weird spotting in place of my period the second month). For the most part, the cup is great and I am 100% happy I took this step.

There's just one thing that's really bothering me. When I have the cup in I feel almost constant rectal pressure. It's not painful, just really annoying. Has anyone had a similar experience? Might the pressure be due to the bell shape of the Si-bell and might a straighter cup be better for me (not sure how else to describe it, but maybe v-shaped)?