This mistress wanted her feet to be licked. As she watched this guy lick her feet, she could tell he was enjoying it given that her feet were sexy. She wanted to make it a humiliating thing for him and that is why she forced him to lick her feet after she had spat on them. Now that made him feel humiliated and it was a little more difficult for him to do.
Sexy Sue knows her beauty allows her to do anything she wants, which is humiliate her foot slave on a whim. Her long legs flex and her pretty little foot is stuffed inside a pair of sky high heels. She's feeling a bit punchy, and daintily spits on her beautiful shoes just so she can order her footboy to lick every last drop off her soles and heel.