"The male anatomy is presented in Figure 4. The male has a penis which is comprised of 3 spongy-like tissue columns that engorge with blood during excitement. A cross-section of the penis shows two outer columns and one column on the underneath side. The average male penis is just that—average, about 4–6 inches as reported by Masters and Johnson. Since the vagina is 3 inches in length and has very sensitive regions near the outside of the vagina and not so sensitive regions deeper inside, the average male can satisfy the average female in heterosexual intercourse. Urine passes from the urinary bladder and exits at the external urethral orifice at the tip of the penis. The penis is attached inside the body to the pubic bone. Figure 2. Male Reproductive and Sexual Anatomy, Cross-sectional View. There are two testicles inside a pouch called the scrotum. One testicle sits higher than the other. On the back of the testicle is a storage compartment where mature sperm end up before ejaculation. This is called the epididymis. There is a muscle called the dartos muscle, not shown, which elevates and lowers the testicle based on temperature and sexual pleasure. Sperm grow best at about 91 degrees Fahrenheit and most males are at about 98 degrees, so the dartos will raise and lower the testicles in colder or warmer temperatures. The testicles produce about 125–250,000,000 sperm every 3–4 days. More importantly, the testicles produce the sex-drive hormone called Testosterone. In males and females, higher levels of testosterone typically mean a higher sex drive. The vas deferens will eventually carry the sperm from the epididymis out of the body during orgasm. The prostate gland swells during excitement and fills with prostatic fluid. The seminal vesicle, located above the prostate gland, also swells and produces a fluid filled with natural sugars."