A tennis elbow type condition caused by excessive, frantic masturbation while viewing porn or frantic, fast masturbation caused by lack of privacy (in dorm room, in men's room at work, etc). Once the condition sets in on one arm, the jerker often switches to the other, to rest the arm which is suffering.
The act of receiving a ferocious handjob preferably with lotion while taping the end of the penis shut with duct tape (must be secured very tightly) until ejaculation has been reached. Pause for 1 minute and watch as the goo oozes out.