The non-dimensionalized size of one's dick in comparison to the dick of B.Fush. One can obtain one's specific dick by the following formula:

S.D. = Your dick's erect volume / B.Fush's erect dick volume

Where the units therein can be in any consistent system of units. Similar factors can be seen in the form of the following:

Specific Dick Length
Specific Dick Mass
Specific Dick Curvature
Relative Dick Roughness

Where all the above would take on the following mathematical form:

Your dick's characteristic / B. Fusher's dick's characteristic

The one caveat to these factors is that they are always less than 1. For instance:

S.D <1

Because B. Fusher has a bigger dick than you. Always