Dear, Cardi: What the hell are you talking about?
The difference between a white penis and a black penis is the same as the difference between a black penis and a black penis or a white penis and a white penis: the specs (length, girth, cleanliness, cut or uncut) but most importantly the user. A dick don't mean jack if it ain't being used right.
You hear that? Hear that tone you're using? That's penis repellent right there!