Lady Karame wanted her slave to drink spit because she had read somewhere that humiliation was a powerful tool and it was very effective. So she collected her spit in a glass and then she made him drink it. And to make it even worse for him, she poured some of it on the ground and she made him lick it from the floor. He had no choice but to do it.
Lady Karame wanted to show this slave that it was not ok to do what he had done. She used her cigarette as well as her spit to punish him. The mistress did not want him to do what he had done again so she used him as her living ashtray and she also spat on him. She whipped his naked body and he learned his lesson the hard way.