I'll Take Care of Your Bully, Step-brother

You come home after a tussle with a bully, and of course your older step-sister is so PISSED. No one touches my step-brother! I promise I’ll set him straight when I tutor him tomorrow. You come home early and find out just how your step-sister plans to persuade your bully to stop, though. It’s not exactly the persuasion you had in mind. You hear moaning and gagging coming from the bedroom and peek in through the door. You see me on my knees sucking then taking his cock in my asshole in doggy position.. Do you say something? Do you stop it? Or do you jerk off while the door gets closed and your step-sister gets banged up against it? ;3