Cryptorchism

[Sarah]

An abnormal physical condition, involving the male reproductive glands, or the testes if you will. It tends to manifest itself during the first stages of sexual arousal. The [erectile tissue] of the penis becomes filled with blood, engorging the penis to a semi-flaccid state. The testes at this point are withdrawn into the body by the arteria testicularis, frustrating the blood absorption process of the penis. The penis violently contracts as a result, contusing itself severely at the base. The spasms will increase until the entire stem of the penis has become purple or black-and-blue in color. Despite the excruciating pain, seminal discharge will begin to leak out of the glans ([penis tip]).
Its recommended to pull back the testes immediately, despite the debilitating pain, to prevent further complications to the male reproductive organ, such as [testicular torsion]. (Where the blood supply to the testicle is cut off because of twists in the spermatic cord.)