"No object may be fully inserted into a vagina if it is longer than the female's Vaginal Depth Potential. In such extreme situations, internal damage may occur, though this is best left to the Aedile. A female's Vaginal Depth Potential equals her height in feet converted to inches (such as a female of 5' 6" becoming equivalent to 5 1/2"), and then (2d20)% is added."