I have been with my S/O quite a while, we have tried almost everything in the book. Recently I got an iud which I love except the fact that my periods are always weird now. We have recently started having unprotected sex and after he cums inside me he fingers me to put it deeper inside me. (I know weird, but it’s my bedroom activity not yours)

Anyway since we started doing that every time he fingers me I start bleeding heavily. But then it stops 5 mins later, I thought I had started my period but I only start bleeding when he fingers me. I tried to see if maybe he cut me on accident but it doesn’t hurt down there. Not sure what to do or think about it.

Can someone explain what it may be?