Mull of Kintyre

Via my friend Steve. This just pegs my urban-legend-detecto-meter, but I couldn't resist an opportunity to write about penises. So here it is:

The Mull of Kintyre test was said to be a guideline used by the British Board of Film Classification in the United Kingdom to decide whether an image of a man's penis could be shown.

The board would not permit the general release of a film or video if it depicted a penis erect to the point that the angle it made from the vertical was larger than that of the Mull of Kintyre on a map of Scotland.

OK, so you can show a penis, but not if it shows any interest in the proceedings.
Best if it's somewhere really boring, like a salad. Wilts like lettuce.

Mull of Kintyre
Paul McCartney & Wings
Almost five.

Penis evolution by PZ Myers at ScienceBlogs - with tumescent turtles.

There are multiple hypotheses about the exact order and pattern of descent of the penis ... but one of the striking things about this pattern is how lineages, such as the birds, can so blithely lose their intromittent organ. ... Think about that… it hasn't been at all uncommon for female vertebrates to be untroubled by the absence of a penis in their mates, and apparently have preferred it that way.

[Update:
More about hydraulics at The Physics of Sex (you just knew there'd be a nexus of the nerdy and the prurient out there).
]

Mull of Kintyre Test at Wikipedia.