The imaginary measuring device guys in personal ads use to measure their penises. The MDR adds anywhere from 2 to 5 inches to the length of a penis.
Ad-reader: "Wow! This guy has 10 inches! Check out this ad!"
Friend: "Maybe if you're measuring with the magic dick ruler..."
Friend: "Maybe if you're measuring with the magic dick ruler..."
by Edo Alonge January 23, 2008
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