A white person who is down with black people without attempting to act black themselves. It is a term of endearment but should still never be used by white people as it could evoke an unintended racial misunderstanding.
Opposite of a whigger
Tyrese: Yo white boy, you got the answers for next weeks test?
Colt: Yeah man, in fact, here are the answers for the rest of the semester
Tyrese: Ohhh shit, you my caucigger!