This slave whimpers at the sight of Jessica and Vivica partly because he misses them but also because he fears them. That's because he can never be sure what kind of mood the girls are in and what they will do to him. Today they seem to want to grind their pretty heels into his skin, which means his whimpering was for good reason because clearly this hurts. But his pain in exchange for smiles on the girl's faces is more than enough reward for him.