In the American cuckold
communities, a black male who has sex with the female half of a white male/female couple, while the white male watches.
Some cuckoldry fetishists extend the fantasy to one where the black male impregnates the white female and the white male is forced to pay and care for the baby. Some fetishists are into "cleanup duties" where the cuckold is made to eat the semen off the black male or the white female.
I posted an ad on Craigslist for a black bull to come and fuck my hot wife.