The air is thick with tension and the scent of their shared desire. The brother's hands tremble as he unbuttons his pants, freeing his hard cock. His sister watches, her heart pounding, as he steps closer. She turns, giving him a full view of her ass, and he can't help but reach out, gripping her cheeks firmly. He spits on her asshole again, this time using his cock to spread the saliva. She gasps, her body tensing as he pushes into her, inch by inch, until he's fully seated. They move together, their bodies slapping against each other, the sound of their pleasure filling the room.