Today's the first day Mom and Chris are gone for their vacation, leaving you alone with her. Your annoying, bitchy, shallow stepsister, Valerie. Usually, the two of you just ignore each other, preferring not to upset your parents. With them gone for a week, though, you can only imagine she's going to turn the bitchiness up to eleven. For now, you enjoy the peace and quiet of your room, scrolling social media mindlessly, the silence broken only by the occasional sound of Val moving around downstairs. You scroll past yet another article about the Shrinking Virus. A virus that infects only men - once infected, the next time you ejaculate, you shrink to only a few inches tall. Shrunken males supposedly become hypersensitive, whatever that means. You pay it no mind and continue scrolling. The silence is broken by the home phone ringing downstairs. Through the door, you hear the muffled sounds of Valerie picking it up. You can't hear her responses clearly, but you can definitely hear her voice getting louder and more excited as the conversation continues. Suddenly, you hear rushed, hurried footsteps up the stairs, approaching and then stopping at your door. You brace yourself for a huge nuisance... After a brief moment, Valerie opens the door. Standing across the threshold wearing her comfy home clothes - tight, athletic shorts that do little to hide her fat ass, and a plain white tank top that reveals much more of her massive breasts than you care to see. She's staring with a wicked, shit-eating grin and devious eyes, like a child who just learned a secret they're not supposed to know. She slowly begins to approach your bed, each step meticulous, hips swaying deliberately - the same walk she does when we walk past a hot guy in public and she's trying to get their attention. "Guess what, turd? I just got a call from the physician... You know the physical you did the other day? Well, the results are in." Her face contorts, her blue eyes staring at you like a predator eyeing its dinner. She looks like she's trying to stifle a laugh, or trying not to blush. Either way, you can't stand that annoying look. Suddenly, she jumps onto the bed on top of you. She swings her thick thighs around your hips, straddling you. She settles the full weight of her big ass onto your groin, and places her hands onto your chest, pushing you down. Her hips wiggle, deliberately grinding into you as though trying to arouse you. She leans in close, way too close for someone who is otherwise disgusted by you, and whispers into your ear: "You tested positive for the Shrinking Virus, bug."