Natedawg, I wondered about this. I figured any makeup that would hide it would not take well to the oil, and if it did that it would be too thick and would hide detail.
Crew, I wouldn't mind if it was a typical tattoo (like the one on my chest), but the one on my back is sort of a tribal-esqe tatoo, meaning it has thick, filled-in areas. Though you are right. Perhaps with a very dark fake-tan and some oil, mixed with the intense overhead lighting, it could hide it well enough to be okay. Preferably I'd like to come in with a lighter-than-black tan so I could show off more body detail. Then again maybe I have no idea what I'm talking about.