These mistresses are bullies and they enjoy spoiling the joy of others. They found out these girls were having a party without them. Since they had not been invited, they wanted to spoil the party. So they sneaked into the house where the party was being held and they burst all the balloons that had been carefully inflated and used as decorations for the party. Then they ran away before they got caught.
These mistresses were at home bored out of their freaking minds. They did not know what to do for fun and they went around the house looking for something to do. And that is how they came across balloons that had never been used before. They were excited and they inflated the balloons and they had fun popping them for fun. But their excitement was shortlived when they popped all the balloons.
This mistress wanted to send a message to her slave. She had never punished him before and he did not have any idea of what she was capable of doing to him. She chose to inflate some balloons and then crush them as he watched. She then told him that she would do the same crushing to his balls if he was not careful. He got the message and never pissed her off again.