Our society has destigmatized many things over the years, but period sex isn't one of them. Fear, disgust and dirtiness have, historically and culturally, been associated with menstruation since Biblical times. In the 19th century, women were told to avoid dancing, shopping and attending parties while on their period. While norms have changed a lot since then, menstruation is somehow still considered taboo. Maybe that's part of the appeal of period sex and why it feels hot to do something that society still finds filthy.
But besides being turned on by bodily fluids, doctors have come through (for people like me) and explained the benefits of period sex for all participants. Erica Smith, a Philadelphia-based sex educator, explained that having an orgasm, or engaging in really any sexual activity, can work for relieving period cramps. “There's taboo around it but period blood isn't any ‘dirtier’ than other fluid exchanged during sex.” So she encourages people to go for it.
Other benefits of period sex can include: