Inside her

"Finish it" Emilia moans. "Fill me with your cum, pump deep inside me while all your girlfriend can do is watch."
You know that it wont take much longer for you to finish, and you pick up the pace again. Emilias pussy seemed to be clinging on to your dick, **** to milk it of every drop.
Emilia locks eyes with Carrie again. "You ready to see your boyfriend emptying his balls inside another girl? Ready to see him fill me up, until theres no drop of his precious cum left to savour? Do you even think", she says, interruped by a moan of you getting faster, "Hes even going to cum for you from now on? Maybe this is the last time you get to see him cum. That is", she turned her head around as good as she could and faced you, her eyes sparkling, "Until the next time he fucks me of course."
You couldnt hold it in anymore and Emilia noticed. "Cum for me, please, please fill my hungry pussy, please give me every last drop while she watches, please give me everything. I need it so bad, please-" And with one of the most intense orgasms of your life, you filled your girlfriends, step-sisters pussy. Pump for pump you empty your cum deep into her, while you look at your girlfriend, still watching Emilia and you, and Emilia, laughing satisfied, her pussy clinging around you still.

After a couple of moments of regaining your breath, you pull out of Emilia, witch makes a dissapointed noice, and lay down on the bed. Emilia, however, seems not quite finished yet. "How do you think she did?" She asks you, looking at Carrie. "I think she did pretty goo", you said, smiling.

"So do i."
Emilia gets on her back, spreads her legs, looks to your girlfriend and purrs: "Come get your reward."
and you watch as Carrie, legs still shaking a bit, comes over to the bed, gets down to her knes in front of Emilia, and begins eating your cum out of her pussy. "Good girl", Emilia strokes her stepsisters head, while you enjoy the show. After Emilia seems satisfied, she gets up, and collects her clothes. "Im gonna go shower now and then head home. She comes over one last time, giving your still half-hard penis a kiss on the tip, licking up some left over cum.
"If you need me helping out again, you can always call me up."

She winks at you, then the bedroom door closes behind her. You look over to Carrie, she still has some of your cum on her lips.