Usually this the term is used in the black community but this can be used for any one that supplicates to a race or races of people while at the same time hating their own
Linda is such an Aunt Tammy, all she talks about is how bad the black community is. She's black.
All girls who say they are "Mixed", Spanish, Puerto Rican or etc, when they are really black are Aunt Tammies.
If you're married to an Uncle Tom of the same race, you're an Aunt Tammy... But that would be impossible.