To attack someone, usually in a frat-style. A group bear hug that is not condoned by the hugged party. Also a group-beating in a friendly fashion (e.g. mercilous smack-down with pillows).
Origins of giving someone a count as to when the attack will commence ("We're giving you to three! Unos-Dos-Tres!")
Alex: "Let's DosTres the new kids."
Adam: "DosTres'ing them is a fantasic bloody idea."
Nick: (gruntlike caveman).
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.