In the dimly lit room, the scent of sex hangs heavy in the air as the siblings engage in their secret game. She leans in, her breath hot on his ear as she whispers her desire for his cum. He resists, but she's persistent, her hands roaming his body, her lips tracing a path down his neck. She takes him in her mouth, her head bobbing as she sucks him eagerly. He can't hold back, and with a groan, he fills her mouth with his warm, sticky load. She swallows every drop, her eyes never leaving his, a satisfied smile playing on her lips.