Black Pedalling
When a white person says something about a black person in conversation that isn't PC and realizes it mid-sentence and tries to correct themselves or remedy the situation.
White teacher to black student..."student, I'm doing a research project on gang members, can you bring in pictures from your neighborhood?" Black student starring back perturbed. White teacher, "I mean, not that I think you live in a gang infested area because you are black, just because I thought maybe you'd want to help me out because I'm too scared to go into an area of high crime." Black student, realizing that white teacher is black pedalling, walks away.