The relation between car size and penis size. The car / penis theorem denotes the relationship between a vehicle owned by a male and the size of his sexual organ. As the size and overall cost of the vehicle increases, the average penis size of that vehicle's owners decreases in a linear fashion.
For example, according to the car / penis theorem, a man who's car is a 1992 Honda Civic (assuming that it isn't riced up) should have a penis size of approximately 7 inches erect. On the other end of the scale, the average male Lamborghini owner has an erect penis length of about 3 inches.
by Qbou3mT March 06, 2015