You test your domination over Isabella by telling her to fuck her brother

You've been wondering just how far you can push your slaves. What wouldn't Emma or Isabella do for you, you wonder.

When you're fucking them later that day you tell Emma to slap her friend in the face. Emma quickly obeys. Then you have Isabella slap your girlfriend back. You have them fight a bit more until you are truly worried they'll seriously injure each other. Your cock is hard as you realize the power you have. Then a dirty thought crosses your mind.

"Isabella," you say as Isabella is making up to your girlfriend by eating her pussy. Isabella stops licking Emma's cunt and turns to face you. "I want you to fuck your brother."