9. I'm Stopped at a Red Light
Unless you're sitting in a car, then your boyfriend should be able to figure this one out.
In a week, once your period is over, then you can give him the green light instead.
You don't have to be blunt and tell others that you're bleeding below the belt, because there are plenty of other ways to state that you're on your period.
What euphemism do you usually use in order to tell others that it's your time of the month?