8 Things You Didn’t Know About Your Penis

 

Sensitivity, pleasure, size, and other surprising facts.

1. Use It or Lose It

You need to have erections regularly to keep your penis in shape. “It has to be essentially exercised,” says Tobias Kohler, MD, assistant professor of urology at Southern Illinois University School of Medicine.
To maintain a healthy tone, the smooth muscle of the penis must be periodically enriched with oxygen by the rush of blood that engorges the penis and makes it erect, Kohler says.
 
 

2. Your Penis May Be a ‘Grower’ or a ‘Show-er’

Among men, there is no consistent relationship between the size of the flaccid penis and its full erect length.
In one study of 80 men, researchers found that increases from flaccid to erect lengths ranged widely, from less than a quarter-inch to 3.5 inches longer.
Whatever the clinical significance of these data may be, the locker-room significance is considerable. You can’t assume that a dude with a big, limp penis gets much bigger with an erection. And the guy whose penis looks tiny might get a surprisingly big erection.
An analysis of more than a thousand measurements taken by sex researcher Alfred Kinsey shows that shorter flaccid penises tend to gain about twice as much length as longer flaccid penises.
 
 

3. The Pleasure Zone

Many men consider the underside of the glans (head) of the penis and the underside of the shaft to be most sensitive to sexual pleasure.
Researchers asked 81 healthy men to rate the erotic sensitivity of different areas of their bodies, including not only the penis but also zones such as the scrotum, anus, nipples, and neck.
 
 

4. Sensitivity Declines With Age

Studies show that the penis steadily loses sensitivity as men age though it’s hard to say exactly by how much. That’s because different researchers have used different ways to stimulate the penis and measure sensitivity.
In general, the sensitivity of the penis is gauged by the least amount of stimulation a man is able to feel. That is called the “sensory threshold.”
 
 

5. Vibrators Work on the Penis Too

Vibrators aren’t only for women. They work on the penis, too. In fact, vibration is so effective on the penis that often men with spinal cord injuries can ejaculate with the aid of a special medical vibrator. For this kind of treatment, the vibrator is usually held against the underside of the head of the penis.
“Medical-grade vibrators aren’t necessarily more powerful,” Kohler says. The vibrators are tuned to stimulate parts of the nervous system involved in ejaculation. “They work at frequencies or amplitudes that are more specific to the [nerve] pathways.”
 
 
 

6. There’s More to the Penis Than Meets the Eye

“Most guys would be proud to know that their penis is twice as long as they think it is,” Kohler says.
That’s because half the length of the penis is inside your body. Just like you don’t see all of a big oak tree above ground, you don’t see the root of your penis tucked up inside your pelvis and attached to your pubic bone.
 
 

7. Your Penis Is a Habitat

The skin of your penis is home to a diverse community of bacteria.
Lance Price, PhD, and Cindy Liu, PhD, researchers at the Translational Genomics Research Institute, in Flagstaff, Ariz., used genetic tests to identify the bacteria found on men’s penises. Their study showed there were a total of 42 unique kinds of bacteria inhabiting the skin of the penis.
 
 

8. Most Men Aren’t Circumcised

Worldwide, approximately 30% of males aged 15 and older are circumcised, according to a 2007 report from the World Health Organization (WHO) and UNAIDS.
Rates vary greatly depending upon religion and nationality, the report states. Almost all Jewish and Muslim males in the world have circumcised penises, and together they account for almost 70% of all circumcised males globally.