It seems like Princess Bella and Princess Beverly are always in competition with each other. Nothing is off limits even slaves. They are in a face slapping mood so they decide to play a game of slap the slave. Princess Beverly loves playing games and predicts she’ll win. Princess Bella says face slapping is her specialty so she‘s going to win. They want to see who can slap the slave the hardest. The slave is not going to be judging the contest he is simply there to be used as a prop. They will take turns each slapping a separate side of the slaves face and then judge the winner by seeing which side of the slaves face is the reddest and most swollen.
After first humiliating the slave by making him oink like a pig the contest starts. They each take a cheek and take turns slapping one at a time like a game of tennis or Ping-Pong. Back and forth they really get into it as the slaps just keep getting harder and harder. At one point Princess Beverly even starts using a crop instead of her hand and you can tell this really hurts the slave. But they don’t care about the slave’s wellbeing they just want to win the game. The contest goes on until the slave eventually
The slave is just a prop to be used by the Mean Girls because they were bored and wanted to play a game. They don’t even consider him to be a human being he is literally just a game piece for them no different than the shoe or any other game piece on a monopoly board.