Stop eating the day before and make sure to enema thoroughly that morning so you can offer him without any reservations any hole he likes. With nothing in your stomach, gagging on his beautiful n i g g e r dick without barfing is possible.
While he is enjoying himself (assuming you please him), ask him, "Do you owe any n i g g e r s money?" then offer to help him work off his debts by servicing them. Even if he doesn't owe them money he can at least whore you out and make some cash off your white ass. If you are really into Black Servitude, it's not a job, it is a vacation!