Cum in Kara's pussy right there.
From Create Your Own Story
After a few minutes of idly bouncing Kara up and down on your cock, your mind awash in a sea of pleasure as her soft pussy caresses your manhood, you feel a sudden tightness surround your cock with Kara shuddering on top of you, the sexy redhead obviously having just cum around your dick. Now that her pleasure has been taken care of, you let your own pleasure take over you; after a few more moments of the girl's ass undulating against your groin, you let out a little, inaudible grunt as your cock spasms and fires off a huge load of hot, sticky cum into Kara's twat, followed by another, much smaller one as you grit your teeth trying not to tip off her brother that you just filled his sister with your seed.
At that moment, Kara suddenly leaps off your cock, jumping to her feet and proclaiming, "Take that, Adam!" You feel the blood rush out of your face as you realize she's still got her shorts down and your huge, honkin' cock is out in the open, glistening with Kara's pussy juice. You look over to Adam, expecting the worst, but find him with his head in his hands, leaning back and groaning in defeat toward the ceiling.
You seize the opportunity and yank Kara's shorts up, then quickly stuff your cock back into your pants and zip up before Adam becomes aware of his surroundings. You're ecstatic that you were finally able to conquer Adam's sexy younger sister, but you can't help but hope to get her alone again tonight for a bit longer than a few minutes.