The angle of a male genetalia's "shaft". A main factor in the USA's proper penis measurement equation drafted by Randy Marsh from South Park, CO. The weight and girth of the penis is divided by the YAW of the shaft, thus equaling the adjusted penis size. *Note: for proper measurement, a scale and protractor must be used to find true yaw.
Sure my flaccid schlong is only 4.1 inches when you measure it with a ruler, but when you factor in my YAW I'm a solid 5.9 inches of pure man steel.