I read it on Literotica some time ago. It was set in the deep south and was in the 20's, 30's....maybe even 40's. It seemed this guy was a racist (possibly even a KKK member) and he was having a conversation with his friend about another man's wife who was getting fucked by a local black man and they even caught her doing it I think. He secretly wanted his wife to do the same. Long story short, there's a barn, his wife ends up being a slut for black cock, yada yada yada. I believe he has a daughter in the story also.