Smitten
To be brutally honest, the public humble-head finds this particular customer-mistress very alluring. He is quite smitten by her! And why wouldn't he be? She's a beautiful goddess! But, of course, he dare not make his feelings towards her known - that would mean a certain whipping for the crime of insolence. Slaves are not allowed to flirt with their betters! Besides, a superb girl like this wouldn't be interested in a dirty slave like him in any case! Haha - the very idea is risible! She barely even looks at him, apart from a quick derisory glance downwards as she switches feet in front of his menial mouth!
All he can do, is ensure that he does a good job of lickshining her sneakers - even if the bright young woman is clearly much more interested in the contents of her text messages (which are probably from her boyfriend) than in the humble-head's dirty tonguework on her dirty footwear.
Haha - look at the slave's sad, rejected face as his ideal goddess eventually turns and walks away from him, without saying a word to him and leaving him with only a mouthful of her sneaker-mud to remember her by! Haha - what a loser he is!