The scrotum is the part of the male genitals that hides behind the penis.
It houses the testicles, which produce testosterone and spermcells, serving as a protective covering.
The scrotum can be large or small, wrinkled or smooth, covered with hair or bare. All these variations are normal.
The scrotum contracts upwards towards the body with cold, fear and in the last phase of sexual excitement, before ejaculation.
The scrotum is sensitive to touch. Some guys enjoy it if you cup the testicles in the palm of your hand, stroking the scrotum.
One way of delaying orgasm is gently pulling down the testicles.

When I go swimming my scrotum shrinks. How come?