Penis
A multipurpose organ responsible for sexual pleasure, reproduction, and the passage of both urine and semen the end of the penis is called the glans which contains the urethral opening that allows urine and semen to pass from the body in uncircumcised males the glans is covered by an additional layer of skin called the foreskin; main part called shaft; the raised ridge that separates the shaft from the glans is called the corona.

Scrotum
A loose pouch of skin covered with pubic hair that contains the testicles.

Testicles (or testes)
Are referred to as gonads and are reproductive glands; produce sperm and make sex hormones, mainly testosterone.

Prostate gland
The prostate sits on top of the bladder and secretes a milky fluid that is part of the ejaculate.

Seminal vesicles
A pair of tiny glands that lie above the prostate which produce about 70% of the seminal fluid, with the remainder produced by the prostate; seminal fluid combines with sperm.

Glans Heald / Penis
The most sensitive area of the penis. Although a great place to stimulate, it can be very sensitive, so you may want to start slow with it until you know what he likes.