Negroes, mulattoes like to spank white girls in all holes. The fact that this brunette is also a charming girl - gives a glamour to what is going on. And he's just using her as a device to jerk off his dick and lick his balls. He uses it and then he flushes it. And she's satisfied.
My brother fucked his sister on the floor like he wanted to. She did not particularly resent seeing his thick cock, and then responsibly jumped around.