Why do they do that thing where they hold your testicles and ask you to cough in physicals?

Checking for Hernias: The most common hernia in men is one that extends into the scrotum. This inguinal hernia, which is a weakness in the wall of the abdomen, can become life threatening if the bowel gets trapped in it and the blood flow is cut off. Some men have no symptoms until they reach that point, so the exam hopes to find hernias before they become emergent.