reds are playing
Your girl is on her period
Bae the reds are playing
red play
The act of oral, digital and/or sexual copulation with a female who's menstruating (or a male or female partner who's bleeding rectally), especially when blood is smeared about salaciously.
She called to postpone their hookup date because her aunt Flo was visiting, but he told her "it's cool, I'm into red play".