Your older sister's footsteps echo down the hall, growing louder and more urgent. You scramble to hide your porn and your throbbing erection, but it's too late. She throws open the door, her eyes widening at the sight of you, panting and flushed, your cock straining against your jeans. She freezes, her gaze locked onto your bulge, her cheeks flushing a deep crimson. "What are you doing?" she demands, her voice barely above a whisper, as the two of you stand there, the sexual tension palpable, your heart pounding in your chest.