Well, I hate to be the one to break it to you, but this is a vulgar synonym for menstruation. I know, it's horrible, but isn't it just damned funny as hell? I mean really. It blows away the ambiguity and shyness of the beauty of the entire menstrual cycle and just opens up to the world. Fuck the period:

I'm on my bloody mess!

I don't fucking care if you vote this down, you hooker.