Gwen has some payback in mind

Gwen is sitting on top of James, hugging him tightly. You hear her whispering something into his ear. James eyes wide in surprise, his thrusts speeding up slightly. After a second he whispers something back into her ear that you read from his lips as "okay". They are up to something.

"Now!" You hear Gwen shout to James, jumping off his rigid cock, leaking cum all over the bed on doing so. They both quickly get up from the bed and grab you by the wrists towards the room. Your sister pushes you into the bed. You try to protest but are immediately smothered by your sister's cum filled pussy dropping down on your face. You taste sperm mixed with your sisters juices as you kick your arms and legs about in a futile struggle for air.

Meanwhile James gets in position between your slender flailing legs and lines up his engorged cock with your flushed entrance. "Payback is a bitch, sister" Gwen taunts you from above, riding your face without abandon. "Time to taste your own medicine and become breeding stock for this perfect specimen"

Your hands still trying to lift your sister's hips high enough for you to breath, you're too distracted to realize the langer lurking between your thighs. James aims his cock carefully and thrusts forward in one powerful motion.

As his glans smashes into your cervix you scream in both arousal and pain. Opening your mouth wide let's Gwen push her well-filled hole even deeper into your face, pouring copious amounts of James essence down your throat.

James gets a grip of your hips and thrusts his whole body forward into you. He seems in a breeding frenzy just like your sister and nothing in the world could make him pull out at this point. You still struggle weakly, trying to get your legs between him and you to push him off, but to no avail. His thrusts getting quicker, breath getting raspier from his one last task for the night - knock you up.

You feel your own body responding to his rough pounding and feel a powerful climax approaching. Hours of watching James fuck the brains out of Gwen with your fingers lodged inside your pussy did their part, it's not long before your legs start shaking and you scream your orgasm into your sisters pussy on your face.

This seems to be the mating call for James , as his pace goes into overdrive and he slams his cock home with all his strength, until, finally, his cock head stays still inside you. You feel it in slow motion: his glans being squished against the opening in your cervix, the pulsing of his shaft, his balls resting against your ass cheeks, twitching in rhythm with his perfect cock and pumping out their last virile load of dangerously fertile sperm. You feel the jets of white hot cum inject from his cock directly into your core. Two, three, four... You can't count them anymore, but your womb fills up with a burning heat that lingers.

Finally James is spent and fucked out for the night, having saved his last load for you. Exhausted the three of you collapse, cum smeared all over your bodies and the bedsheets. It is done. Now it's up to Chance whether his little swimmers will conquer your egg and seal your fate....

The three of you fall asleep in your sisters bed