Cristine, the insatiably curious sister, can't resist her brother's allure any longer. As he lounges on the couch, she approaches, her eyes locked onto the growing tent in his pants. She bites her lip, her heart racing as she reaches out, her small hand wrapping around his hardness. He looks at her, surprise and desire warring in his eyes. "Cristine, this is... wrong," he stammers, but she's already on her knees, pulling down his pants, revealing his thick, pulsating cock. She licks her lips, her eyes gleaming with lust as she takes him into her warm, wet mouth, her head bobbing up and down, her tongue swirling around his sensitive tip.