hybrid cross between "grow a pair of nuts" and "man up"
Guy 1: "Oh man, I totally wanna bang that chick over there."
Guy 2: "So nut up and do it already!"
A political candidate who is both campaigning for public office, and complaining about another candidate campaigning for the same position.
Person A: "So what have you seen about that governor's race in Minnesota?"
Person B: "A whole lot of camplaining. One candidate was crying about yard sign placement. Another candidate was whining about comments they made being taken out of context. I can't wait for this round of elections to be over with..."