In the quiet of their shared bedroom, a curious sister can't help but sneak glances at her brother's growing bulge. He catches her staring, and the tension between them thickens. She licks her lips, her pussy throbbing with desire. "You're so big," she whispers, her voice hoarse with need. He smirks, pushing her onto the bed and pulling out his massive cock. She eagerly takes it into her mouth, her hands cupping his heavy balls, ready to please her brother in the most intimate way.