Mull of Kintyre rule

Alternative forms

 * Mull of Kintyre test

Etymology
From the shape of the Mull of Kintyre peninsula in Scotland, which somewhat resembles a flaccid penis.

Proper noun

 * 1) According to an urban legend, an unofficial guideline used by publishers and the media in the United Kingdom to decide to what degree of erection an image of a penis can be shown.