In the dimly lit hallway, a sister's gaze lingers on her brother's bulge, her curiosity piqued by the growing tent in his pants. He catches her staring, a mischievous grin spreading across his face. She bites her lip, hesitating, before giving in to her desires. Kneeling before him, she unzips his jeans, her heart pounding as she takes in his size. She tentatively licks the tip, his salty pre-cum sending shivers down her spine. Her inhibitions fade as she takes him deeper, her head bobbing in rhythm, his moans encouraging her.