BLUE BALLS - Sexopedia Term 7

Blue Balls is a slang term used to refer to the pain or discomfort a man experiences in his scrotum from prolonged arousal without ejaculation. When a guy gets turned on and doesn't climax for a longer duration, it can cause an aching sensation in his balls.
It is not something to worry about, and it is not dangerous and doesn’t cause any damage to his organ. It also refers to indicate the uncomfortable or frustrating feeling for not being able to ejaculate the load.
Scientifically, blood rushes to his penis when a man gets aroused. And when it doesn't get released, the resulting built up pressure gives an uncomfortable feeling. Eventually, blood goes back and genitals go back to normalcy.
A note of caution for women; Never let a man use blue balls as an excuse to pressure you into sex. He can always use his hands to jerk it off.