Occurring in males after sexual intercourse or masturbation, the inside of the epididymis become inflamed and painful with a burning sensation, likely due to seminal fluid remaining inside the epididymis following ejaculation. The Burns takes time to go away, and men suffering from it should sit on the toilet with their penis aimed down to allow for sufficient drainage. If this is a common problem, you should speak to your doctor.
After wanking it with Sally, I got the burns. Took like ten minutes to go away.