In the sport of soccer, a Nut Trap occurs when you get a ball kicked to you. The ball is flying towards you and you think of either trapping it with your thigh or your chest. You misjudge the flight pattern of the ball and as it approaches you switch from either thigh trapping the ball or chest trapping the ball, to the opposite. As the ball is about to hit you, you realize that its going in the middle of those two areas and you know you're in trouble. The ball then hits the crotch area. Because you are both trying to trap it with your thigh/chest, you make a sort of C position and the nuts cradle it like when you catch an egg. This trap is actually, quite effective if you can withstand the pain.
Wow, that kid just took a nut trap, I wonder how he is feeling.