If there aren't genetics, there's the purely physiological. Like seeking's dick dragging on the ground. Like a dick wider than your hips. Like a dick with so much volume you pass out from blood loss at the sight of some hot ass. Like a dick so big you can't get your hands around it enough to continue jelqing or clamping.
Red I don't know what to do with your sig, vomit or rub one out.