I did period sex a few times with an ex coz she sometimes got extra horny on her period.
Clean up wasn't actually too bad, but she didn't have heavy flow.
Can't imagine doing it with a stranger though.
I did it once and it was like a murder scene, I had chunks of shit all over me not just blood, never again lol
Prob some sort of health/hygiene rules around it for brothels plus prob don't wanna deal with potential cleanup