Kat's tongue is bruised and ruined from her last therapy, but Dr. Mercies decides to put it to more work. Kat craves hard challenges, and the doctor doesn't want to treat her half-way. So he takes her filthy tongue to the rim gym for some extreme rimjob training. She eats Dr. Mercies ass while doing various exercies until the is huffing and puffing and dripping sweat. But the only way she is allowed to catch her breath is by breathing the air from his ass. He throws in some rough gagging and rude facefucking, then feed her a patient sperm meal. She was a good patient who left Dr. Mercies proud.
