Cramps when sitting or lying down

[alloverxx]

So, I'm fairly used to the cramps I get on my period. This is the first time I've used my Lena cup during my cycle, and I've noticed that when I'm sitting or lying down, I get some cramps.

I tried removing the cup and sitting down, and there was no cramps but as soon as it was back in place and I was sitting on the toilet, the cramps were back. However, when i stand up the cramps are gone.

Any ideas about what I can do for these cramps?