Doggy

Instead of answering directly, you get up on your knees and behind Emilia. She understands immediatly. She gets down on her arms and legs , and you pull down her lingerie, finally exposing her shaved pussy. With her on all fours you not only get the best view of Emilias ass, but are also almost directly in front of your girlfirend, which masturbates faster as she watches you assume position.
You do not need to worry about using a condom, Emilia, much like your girlfriend, is on the pill-at least for now. So you grab your dick, still covered in Emilias spit, and align it with her shaved pussy, which is shining a bit in the light.
"You´re already wet", you remark, you let one finger glide across her pussy, making her whole body shiver. She turns her head around and locks eyes with you. "I just cant wait for you to take me."
Your eyes wander up to meet your girlfriends, which, almost trance-like, just nods, and mouths: "Do it". Then your gaze wanders back to Emilia- Her blue eyes seem to beg for your cock to finally fill her, she bites her lip in aspiration. You take one deep breath, then you grab your girlfriends step-sister by the hips-and enter her.
Immediately you meet resistance. Even your girlfriends pussy, which should be used to your cock by now, has trouble taking it all in at times, but this is on another level. Emilia is so tight that, even besides her wetness, you realize that this might be harder than you thought. You dont even manage to fit your Penis halfway in with the first push, besides you not beeing that gentle.
"You´re tight", you grunt, as you pull out a bit, just to go back in even harder.
"Then fucking stretch me!" Emilia yells, her sentence beeing interrupted by her own moan as you ram back into her again. Soon the moaning turns to ecstatic screaming as Emilia begs you to keep going. You now manage to fit almost your entire Cock into her, feeling it hitting her walls, filling her completely. "Fuck, keep going" . You didnt plan on stopping either way, but feeling extra encouraged you grab her hair to create more speed. Emilia, now seemingly satisfied by the pounding shes receiving, turned her attention to your girlfriend.
Their faces were lmost at the same level, and you could only imagine what Emilia and you looked like from Carries perspective. Her step-sister bend over in front of you, obedient to your cock, begging for more, the sweat on her body making her skin shine bronce, like a greek goddess. And behind her-you- her own boyfriend, grabbing this girl by the hair while fucking her from behind. Your muscles shine in the light, your body moving heavenly, yet she, the girlfriend, out of range to touch or feel it, doomed to sit and just watch, and yet taking this much pleasure out of it.

Emilia seemed to lock eyes with Carrie. "You like that?" In the reflection of the window behind Carrie you could see Emilia smile. "You like beeing your boyfriend fuck another girl rather then you, making her his bitch while you watch, masturbating like a little slut?"

Carrie nodds, a moan creeping from her lips.

"I didnt hear you" Emilia was out of breath yet demanding in her voice. "No point in denying it, we all see how much you enjoy yourself."

Carrie seemed to hesitate, then she bursts out: "I love it! Im such a fucking slut and i feel so humiliated yet so horny, fuck." Her eyes wander up to meet yours. "Please fuck her harder"

You would be a bad boyfriend not to fullfill her demand and so you upped the pace again. Emilias legs are shaking, her face now pressed down on her pillow, her biting down on it, moaning in to it.
You got it-your Dick was a lot to take. Yet you continue, until something changes in Emilias demeanor. Her voice turns higher, her moans more frequent.
"Shes going to Cum on your dick.", Carrie remarks, mesmerized. She seemed close as well, moving her hand faster and faster. "Do it." Her eyes met Emilias. "Claim my boyfriends dick, cum on him while i watch.
Emilia screamed in a high pitched voice, her hands grapping the pillows tightly. "Fuck, dont stop, please dont stop, oh my god, im gonnna fucking."
and at the same time, both women in the room came. You didnt stop, fucking Emilia through her Orgasm, while Carrie was reaching her climax by herself. Her eyes were fixed on you, and the girl in front of you, completely submitting to your dick.

it took some moments for Emilia to regain her breath, but you werent done yet-and neither was she.