@Jeff: That's definitely not true of me. Every crevice which I can see is the same color as the surrounding skin, from my toes to that crease where my throat meets the chin (and that last one was damn hard to get a look at).
@Jim: I know you're trying to be a metaphorical asshole, but the question was prompted by having the misfortune of seeing a literal one at the clothing-optional park yesterday. Since the owner of the orifice in question was really fit and completely hairless I assume that he was either gay, a bodybuilder, or both. Either way he presumably is very thorough in his personal hygiene. I have no idea whether I'm one of the people who have the thing I described going on myself, but based on what Jeff said, I probably don't; my skin seems to be uniformly pallid all over.