Mistress Kitty is a cruel mistress. She wanted her slave to learn a cruel and painful lesson so she strangled him. She used her bare feet to do it by stepping on his neck and jumping on his stomach and on his chest. She made him nearly choke and she made him feel a lot of pain. That taught him the cruel and painful lesson that the mistress wanted him to learn.
Madame Marissa came home and found her slave lying on the couch watching movies when he had not done the chores she had given him. She was pissed and did not want that to happen again. So she sat on him and used a string to choke him. She also used her hands to compress his throat and humiliate him. He could not do anything about it as she made sure he was tied up and helpless.