In any undertaking, it helps to know exactly what you are dealing with.

To understand which enlargement methods are the best, it is helpful to know how the penis is made up, how it works, and how the enlargement methods work on your penis.

As you can see from the diagram above, there are two main chambers to the penis, the corpora cavernosa. These chambers fill with blood during arousal, and the tissues become engorged.

As the expansion of these chambers puts pressure on the tunica albuginea and the blood is trapped in the corpora cavernosa, the penis becomes erect.

The corpus spongiosum also fills with blood, but to a lesser extent than the corpora cavernosa. This is to protect the fragile tissues of the urethra, and permit ejaculation.

The capacity of the corpora cavernosa is the important factor that determines the size of an erect penis. The penis can only become as large as the chambers can allow for, as the erection is dependant on the size of these when fully dilated.

Most penis enlargement methods other than surgery aim to increase the capacity of these chambers, to allow more blood into the penis during erection.

Corona: The 'crown,' a ridge of flesh demarcating where the head of the penis and the shaft join.

Corpa Cavernosa: The corpora cavernosa are the two spongy bodies of erectile tissue on either side of the penis which become engorged with blood from arteries in the penis, thus causing erection.

Corpus Spongiosum: The spongy tissue surrounding the urethra. This tissue expends to protect the urethra when filled with blood, but to a lesser extent than the corpora cavernosa.

Cowper's Glands: The Cowper's glands secrete a small amount of pre-ejaculate fluid prior to orgasm. This fluid neutralizes the acidity within the urethra itself.

Dorsal Side: The top or upper side of the penis.

Ejaculatory Ducts: The path through the seminal glands which semen travels during ejaculation.

Epididymis: The epididymis is a 'holding pen' where sperm produced by the seminiferous tubules mature. The sperm wait here until ejaculation or nocturnal emission. 

Foreskin, Prepuce: A roll of skin which covers the head of the penis in uncircumsized men.

Frenulum, Frenum: A thin strip of flesh on the underside of the penis that connects the shaft to the head.

Glans: The glans is visible in the illustration as the head of the penis. The glans in uncircumcised men is usually covered by the prepuce. The glans is highly sensitive, as is the corona, the ridge of flesh that connects the glans to the shaft of the penis. 

Head: Also known as the glans, this is the bulbous tip of the penis.

Meatus: The opening at the tip of the penis to allow the passage of both urine and semen.

Perineum: The area between the scrotum and anus.

Prostate Gland: Produces a fluid that makes up the semen. The prostate gland also squeezes shut the urethral duct to the bladder, thus preventing urine from mixing with the semen and disturbing the pH balance required by sperm. 

Pubococcygeus Muscle: Also known as the PC or pelvic floor muscle, necessary to control urination and ejaculation.

Raphe: Visible ridge running from the meatus to the perineum across the scrotum, formed during fetus development and gender assignation.

Scrotum: The scrotum is a sac that hangs behind and below the penis, and contains the testes, the male sexual glands. The scrotum's primary function is to maintain the testes at approximately 34 C, the temperature at which the testes most effectively produce sperm. 

Semen: Fluid produced during ejaculation, made up of 2-5% sperm. The main bulk of semen is seminal plasma, with large concentrations of Zinc, and amines that protect the sperm from the acidic environment of the vagina.

Seminal Vesicles: The seminal vesicles produce semen, a fluid that activates and protects the sperm after it has left the penis during ejaculation. 

Shaft: The main length of the penis made up of the corpora cavernosa, corpus spongisum, urethra, cavernosal artery and dorsal vein and artery.

Smegma: A substance with the texture of cheese made up from oils secreted by glands on each side of the frenulum, combined with skin cells, and moisture. This usually only occurs in uncircumcised men.

Testes, testicles: The male sexual glands, the two testes within the scrotum produce sperm and teStosterone. Within each testis is a kilometer of ducts called the seminiferous tubules, the organs which generate sperm. Each testicle produces nearly 150 million sperm every 24 hours. 

Urethra: Passageway of the penis, carrying urine from the bladder and semen from the testes to the tip of the penis.

Vas Deferens: The ducts leading from the epididymis to the seminal vesicles. These are the ducts that are cut during the procedure known as vasectomy.

Ventral Side: The bottom, or underside of the penis.

Penis Enlargement Terms

PE: Used to mean Penis Enlargement, and also Penis Exercising

BPEL: (Bone Pressed Erect Length)- erect penis length measurement, taken from the pubic bone

NBPEL: (Non Bone Pressed Erect Length)- erect penis measurement, taken from the base of the shaft

BPFSL: (Bone Pressed Flaccid Stretch Length) measurement of the flaccid stretched penis from the pubic bone to the tip of the head (glans)

NBPFSL: (Non Bone Pressed Flaccid Stretch Length)- measurement of the stretched flaccid penis from the base of the shaft to the tip of the glans

BPFL: (Bone Pressed Flaccid Length)- flaccid penis length measurement taken from the pelvic bone

NBPFL: (Non Bone Pressed Flaccid Length)- flaccid penis length taken from the base of the shaft

EG: Erect girth, usually measured around the middle, or thickest point of the shaft

FG: Flaccid girth, usually measured around the middle or thickest point of the shaft