An Irish couple was watching a discovery channel special about an African black bush tribe.
The men in that tribe all had 24 inches long penises. When the black male reaches a certain age, a string is tied around his penis and on the other end to a weight. After a while, the weight stretches the penis to 24 inches.
Later that evening as the husband was getting out of the shower, his wife looked at him and said: How about we try the African string-and-weight procedure?
The husband agreed and they tied a string and a weight to his penis.
A few days later, the wife asked the husband: How is our little tribal experiment coming along?
Husband: Well, it looks like we're about half way there.
Wife: Wow!!! You mean it's grown to 12 inches?
Husband: No, it's turned black.
Note: please do not try this at home.