With dominant women, rewards can be a strange thing. That's because sometimes they mean pleasure and sometimes they mean pain. Sandy is happy that her slave keeps the house clean as expected, so she rewards him today by biting into his flesh. Her teeth go deep, digging into his fragile skin repeatedly as he attempts to endure the pain with minimal screaming. Even though he is suffering he realizes this is still a reward, that by suffering her bites he is ultimately pleasing her. At the end of the day that's all any slave wants, to bring a smile to his female owners face.