What you tell your son or daughter before you know they are going to get a high on marijuana. Something you tell you boyfriend/girlfriend before you know they are going to smoke a blunt. Something you tell your friend before he hooks up with rando at the bar.
Hey johnny, don't go catchin herpes now.
Hey bri, be home by twelve, and don't go catchin herpes.
I know your cheating on me, but I still love you, but don't go catchin herpes.