How to tell my male teachers?

I am in the 8th grade and all my teachers are males. I am scared that my period will start in one of those classes and I don't no how to tell the that I need to go to the bathroom. My friend had that happens to her and they asked her why she had to go lol. But I am really scared on how to do that plz help and give advice on how you did it thx you so much