Catalina's heart races as she hurriedly tries to cover herself, her sister's presence adding a thrill to her taboo pleasure. "What are you doing?" her sister asks, her eyes lingering on Catalina's cock. "It's...it's complicated," Catalina stammers, her cheeks flushing. Her sister steps closer, her gaze hungry. "Show me," she demands, her voice barely above a whisper. Catalina hesitates, then tentatively reaches out, offering her sister a taste of the forbidden pleasure she's been hiding. Her sister eagerly takes it, her lips wrapping around the head, her tongue exploring the slit. Catalina gasps, her body trembling with pent-up desire and the unexpected turn of events.