Does this happen to anyone else?

Caitlyn • Rainbow baby boy born 8-7-20
So.. This may sound kinda gross but I'm really curious. Sometimes during sex with my fiancé, I feel like I have to poop. This mostly happens doggie style but sometimes happens in other positions. It's sometimes a little uncomfortable because I'm  more focused on that than the sex. Why does this happen? And does this happen to anyone else?