He does, and attacks Mandy!

Mandy moans on top of you, oblivious of Sam's inaction behind her. You feel him pull out of you, slowly, careful not to make a sound. Seconds after he's left you completely, Mandy lets out a yelp as Sam pulls her down. "Aah! What the FUCK are you doing, Sam?!" "Getting myself two slaves instead of one." "What? You can't seriously- Ah!" You can barely see anything from your position, just the sight of Sam's ass bucking up and down as he fucks Mandy! "That's right, bitch!" You gleefully say, "Who's the fucking **** now?" Of course, you'll be pretty much a **** after this, but not quite. Maybe you can still get out, later!

Mandy isn't letting Sam's betrayal go quietly, though. She's now screaming at him with just as many insults as you did, earlier, and with an equal lack of results. You lay back and laugh. You can't wait to see Mandy as an obedient little ****! But then, suddenly Mandy breaks away from Sam! Fuck! She manages to get off the bed, but before she can get very far, Sam catches up to her, grabbing her from behind. "Why are you doing this Sam?!" "Because you treat me like shit, " he says, lifting her over his shoulder. She hits him on his ass, but he doesn't care. "You are a good fuck, sure, but also a complete bitch. Besides, I've seen how you tear through 'boyfriends'. Whatever we had would have over by next week anyway." He throws her on top of you, which knock the wind out of you both. To make matters worse, Sam jumps on right after her, piling yet more weight on you.

She struggles briefly, but after a little while he's got her completely immobilized beneath him. As it happens, she ended up laying perpendicularly on top of you, her belly pressing against yours as Sam holds her down. Sam looks at you as he begins fucking Mandy. "You'd better bet I'm going to fuck you so hard you won't be getting up for a week after this, bitch!" You don't respond, you just lie there, constantly jostled by Sam fucking Mandy on top of you. He leans over her so his head is next to hers. "You feel that, whore? Once I win this and my cum gets inside you, I'll fucking own you. You'll be my ****, like you were always meant to be! Isn't that right, Cindy?" "Fuck, yes! Take the fucking bitch!" Sam does just that, fucking Mandy harder and harder. It actually hurts you a bit, and you struggle to breathe with their weight on you, but it's for a good cause. You feel every thrust, hoping with each one that this will be the one. It's coming, all three of you know that. That last, glorious pump, when the floodgates open and your lives are changed forever. This is absolutely not how you expected this to go, but at least you have it better than Mandy!

Then it arrives. Mandy clearly feels it coming, as she cries and screams beneath Sam, but he holds her tight. Then he groans, and you see his entire body shudder as he presses deep inside of Mandy. Her screaming stops immediately, now she just softly moans as Sam empties himself into her. When he's done, he collapses on top of her. And, therefore, you. It knocks the wind out of you again, and you struggle to breathe until Sam helpfully lifts himself back up, letting his softening dick slide out of Mandy's creamy hole. Mandy rolls around and launches herself at Sam, embracing him and kissing him all over his body. "Thank you master! Thank you thank you thank you!" "It's alright, ****. I'll let you make it up to me later. First, though..."