To better understand how Viagra works, it helps to understand how the penis works as well.

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Anatomy of the Male Penis

For many people, talking about the penis is tough. This area of the body is considered private and isn't discussed publicly (well, not in polite company). However, the penis is simply a part of the male anatomy designed to accomplish a task, and we'll treat it that way here.

In the case of the penis, there are actually two tasks that it handles:

  1. releasing urine from the bladder, known as urination
  2. releasing sperm and seminal fluid from the prostate gland, known as ejaculation

Viagra helps with the second task: ejaculation.

When things are working properly, ejaculation is a three-step process:

  1. The man becomes sexually aroused.
  2. The penis responds by becoming erect.
  3. Stimulation of the penis causes ejaculation.

That sounds simple enough, but in many cases, step two doesn't happen, making step three difficult or impossible. Although the man is stimulated, the penis doesn't become erect. To understand why, you need to understand the technology of an erection.