To provide cover for illicit activity. To provide a false alibi or to cover up someone else's nasty behavior.
You want to cheat on your wife, go ahead. But don't ask me to cover for you- I'm not your Joe Paterno.
If the cops call, you're on your own. I'm not your Joe Paterno.
Don't do that in front of me. You're not Jerry Sandusky and I'm not Joe Paterno.
He shoplifted that CD, then expected me to Joe Paterno him.
She told her mom she was spending the night at my house when she was actually with her boyfriend. She should have warned me ahead of time if she expected me to Joe Paterno her.
After hearing or witnessing something that would normally get a person upset, it is the act of turning the other way and pretending like it never happened.
Guy #1: So...did you hear that Jim knew that girl was being raped and did nothing?
It is said of the situation where a person has the bad luck to make contact with his testicles against an undefined surface or object, intentioned or not.
Given the nature of the word, it is more appropriate to design cases where the interaction is made with a moving object, for example, a ball.
Although it is extremely painful for the victim, it tends to be considerably funny to people who witness it.
Today in the baseball game the pitcher took a nutshot; the baseball hit him in the nuts.
Man, I just watched the funniest nutshot video ever.