She stood there, wide-eyed, her jaw dropping in shock. Letting go of Billy's head, she reached up to touch the gooey fuck cream sticking to her.

A look of disgust crossed her face, and she backed away from him, grabbing her T-shirt off of the bed and wiping herself with it in hurried, violent motions.

Billy sat on the floor, trying to catch his breath. His prick had shriveled slightly, drops of cum still escaping from the tip.

Cindy sat down on the bed and watched him. Her nipples had become soft again, and Sally gazed at them, entranced by their lovely pale pink color and at the perfect porcelain skin that surrounded them.

Now is the time to go in there and break this scene up, Sally thought. Things have gone much, much too far. She took a deep breath, put her hand on the door and… stayed where she was.

"God, Billy, that was disgusting," Cindy said. "What was that white stuff that came out of your cock?"

"Cum. Don't you know anything? When a guy gets real excited, his cock gets stiff, and then, if he's fooling around with a girl or maybe fooling around with himself, he ends up shooting his wad. It's normal, you know!"

"Well, I think it's disgusting!"

"Aw, come on, Sis. It makes me feel real good."

"I could see that."

"Well, how would you like me to make you feel real good?"

"I-I don't know."

"If you take off your pants, I could make you come, too!"

"Gee – are you sure?"

"Sure. I've learned a few things lately. I know exactly where to touch you to make you come!"

"Tell me how."

"I won't hurt you. Just take off your pants and panties, and lie back on the bed."

Sally was just too curious now to intrude on the two teens. In a strange way, she was proud of Billy for taking charge the way he did. He was sexy as hell, and it excited her to watch him being manly with his sister.