Immobile
The slave must kneel immobile on the floor of the coffee shop beneath his mistress’s chair and study the backs of her boots and socks whilst she sips on her warming cup of coffee and checks her text messages on her mobile phone. The slave has nothing else to focus on, since he doesn’t own a mobile phone. And, even if he did, no one would ever ring him or text him. He’s just a dumbass slave.
Note how the loyal slave steadfastly refuses to be distracted by the equally appealing sneakers and socks of his mistress’s friend seated opposite her.