It goes great!

Anna looked at the feet in front of her, and begins by licking underneath the toes. Instantly her mouth is filled with the strongest vinegary taste she had ever experienced. Her cock goes from limp to fully erect in seconds, and she hungers for more of Marlene's toejam.

"I see you enjoy my toejam a lot, slut. I guess I know what to feed you for breakfast every morning when you become my servant." Marlene said, idly stroking her own cock as her snake hair starts licking it. "I'll make you eat it out of a dog bowl while I plow your slutty ass and fill you with cum. How does that sound?"

Anna starts stroking her own cock as she licked up all the thick globs of toejam inbetween Marlene's toes. The vinegary taste and the thick, gooey, and creamy toejam were the only things she could think about. She was already Marlene's little slut.

Soon enough not a single speck of toejam remained, and Anna showed the massive glob of the black substance in her mouth off before swallowing it. "Well done. I see that you are very good at your job. Now..."