Karen

As you work your cock, your mind drifts to the imminent arrival of the Blake family. Sudden images of Jenna's sister pop into your head, and your prick pulses with the sudden, dirty thought. Karen has fuller lips, fuller breasts and beautiful red hair, which you've always had a thing for. Her butt, while not as taut as Jenna's, is rounder and more bouncy, as you've noticed before whenever she's around. You have always though she was sexy, ever since high school, and occasionally wonder if you had pursued the wrong sister.

As the images of Karen's beestung lips moving up and down your shaft explode into your mind, you pump harder at the forbidden fantasy. Small nuggets of shame only serve to intensify the thrill of the scene playing out in your minds eye. Your heart pounds as you imagine throwing her down on bed you share with her sister and parting her pussy lips with your prick, feeling the rhythmic slap of your hips against that generous ass. Soon, the sound of blood rushing in your ears is louder than the spraying water, and with a frenzy of pumps, you shoot your load onto the shower wall, imagining your cum painting Karen's face.
As soon as your orgasm passes, you snap back to reality. You better curb your little fantasies when she gets here, you think to yourself. It wouldn't do to have any misunderstandings happen.
You exit the shower and towel off, checking yourself in the mirror as you pull on a pair of board shorts and throw a t-shirt over one shoulder. You have decent shoulders and arms, and Jenna always tells you that she could bounce a quarter off your ass, but you still have a little bit of a gut that won't go away. No grey yet in your brown hair, and minimal chest hair, which is good considering that Jenna doesn't care for it. A couple of scars from youthful risk behaviors aside, you aren't wholly displeased with yourself.
Reminding yourself that there's stuff to be done before everyone arrives, you head out of the bathroom, and abruptly run straight into....