Anonymous

Sexual arousal is one of several stimuli that produce contraction of the dartos fascia.

Anonymous

your penus hardens, tightening the balsac

Anonymous

Because muscle fibers in the scrotal skin contract. The suspensory muscles contract to pull up balls. Partly to protect balls from damage and possibly to shorten sperm travel to seminal vesicles.

Anonymous

Not only does it pull skin from the balls to get larger. But with sexual arousal, comes not clothes, which means the balls are exposed, making them colder, so shrinkage happens

Anonymous

It gets tighter has the penis becomes erect.

Anonymous

the penis "grows" pulling "extra" skin from the scrotum area tight