At a guess , one of the earliest racist stigmas used to demonise blacks in America is the idea that they are sexually different size , behaviour etc and that this would ruin a woman . You can see evidence all over modern pornography , with the sub genre specifically for first black cock and even in our language with the phrase Once you go black you never go back . I expect that this is present on escort adds because 1 . The escort may be racist or 2 . to reassure racist whites . The ideal of ' unspoiled woman ' is a powerful social delusion . There may also be the belief that blacks are more prone to violence , crime , drug use and sexually transmitted diseases particularly AIDS <| sep |> Wake up earlier <| sep |> I do well with stupid jokes and tidbits of knowledge no one cares about .