Many women do more than that when they're alone with themselves. But the contrived rules do not allow them to relax with a partner. It is not without reason they say, that a smart woman has it in her head, a fool has it in her mouth. I even know men who categorically reject such liberties.
She doesn't just have big tits, the dark-skinned chick's tits are huge! It's understandable that a nigger enjoys fucking a chick with his mighty cock.