There are a few basic facts about the penis that almost every guy knows. For example, most men are aware that rubbing this flesh feels pretty darn good. Most men also know that partner encounters without protection can expose them to unpleasant infections or unplanned pregnancy. All of this information is pretty basic, but knowing some other important facts about the penile anatomy can help men make better decisions about daily penis care. For instance:

1) Some of it is on the inside.

Obviously, a good portion of the penis is located outside the body and visible to the unaided eye. On the other hand, many men are not aware that the penile tissue continues on the inside. In fact, there's an entire column of tissue on the inside of a man's body that is approximately as long as the outer tissue; among other things, it provides support for the thrusting that takes place during intimate contact. The aspects of penis care that involve supporting healthy circulatory tissue - such as exercise, eating right and drinking plenty of water - apply to this inner tissue as well as the visible penis.

2) The underside is best for pleasure.

Scientists performed an experiment and asked men to rank which part of the penis was the most sensitive to touch. An overwhelming number of men reported intense signals of pleasure when they were touched on the underside of the tip of the penis or the underside of the shaft - something to keep in mind during personal explorations, as well as encounters with a partner.

3) Smoking makes it smaller.

The penis relies on an adequate supply of blood in order to expand during an erection. Since smoking can clog up the blood vessels penile tissues rely on, it's not surprising that puffing away can lead to a significantly smaller penis. In fact, a loss of a few inches isn't uncommon in men with a heavy smoking habit. Smoking can make sex harder, too, as men who smoke tend to huff and puff during any kind of exertion and often lack the stamina of their non-smoking counterparts

4) Masturbation is a common cause of injury.

Injuries to the penis can take occur in response to any of the following:

- Rough sex

- Sports

- Inattentive children

- Poorly fitted clothing

- Pets

But the most common injury comes from masturbation. That's right: Men who get busy with their hands when they're alone tend to do a lot of harm to the skin, the blood vessels and the nerves of the manhood; and this kind of damage can take months and months to heal. Loss of sensation is one of the most common masturbation-related complaints; so at the very least, men should be sure to use a personal lubricant for every session and follow up every day with a quality moisturizing crème.

5) The tool needs to be used or it will shrink.

Every time a man has an erection, the skin of the penis is stretched tight. That stretching is helpful for the skin, as it ensures that the tissues remain loose and flexible. Men who simply can't get aroused, for whatever reason, may develop skin that's stiffer and less resilient, and that might mean that they can't stretch out as far, even when they do feel a little spark of desire. Again, that could make the penis seem smaller.

6) An entire colony of bacteria lives on the skin of the penis.

A daily wash with soap and water can keep things looking clean and smelling fresh, but that scrubbing doesn't always impact the number of bacterial cells that call the skin of the penis home. These cells live on the sugars found in a man's urine, and they also can feed on discarded skin cells. In general, they cause no harm at all. But when the colonies are triggered by chemical changes to grow rapidly, they can cause a distinctive, fishy odor. Thankfully, a penis health crème (health professionals recommend Man1 Man Oil) can keep these bacterial colonies in check. Quality products contain a mix of vitamins that can support the skin's immune function, so the bacteria doesn't take over and cause a smell.