Vitiligo is the exact opposite of what you describe. It is the absence of pigmentation.
The glans penis has a unique epidermal layer (different skin) for the shaft or the rest of your body. It is often a slightly different color. As orgasm approaches, most men become highly engorged and turn a purplish hue. This tells women that you are about to pop. But it also becomes more and more sensitive as it becomes more and more swollen.
This has nothing to do with masturbation. It is only what a penis is like.
Posted: 28 Sep 07:43