Again Julie lifted her mouth.

"You don't have to be still, honey," she said in a whispery voice. "You can move all you want."

With a grunt, Bobby arched his ass up and Carol saw the head of his cock stab between his mother's lips. Julie gave a soft cry of pleasure and let her son fuck her mouth for a while. Then Julie began to ram her mouth down as her son came up. Carol's legs were weakening as she watched. It was intensely fascinating to her, seeing Bobby fucking Julie in her mouth. The sounds coming from Julie sent shivers of feverish pleasure through Carol's body, making her cunt burn with a fierce hunger. Carol licked her lips, almost feeling Bobby's cock in her mouth, too.

Although Carol had sucked cock before, she had never seen anyone else do it. Watching her sister with her mouth filled by a hard cock was exciting her more than she would have suspected. Bobby, as young as he was, didn't have a large cock, and it looked to Carol as if it would be very easy to take his prick completely into her throat. She was hardly aware that she was swallowing time and time again.

Her cunt was burning against the wet crotch of her panties and she felt as if she would come as she watched them. The cheeks of her ass bunched up and then relaxed, only to bunch up again. She squeezed her thighs together and the pressure on her puffy cunt was almost too much for her to stand.

"Suck hard, Mom!" Bobby grunted, ramming his cock up into his mother's mouth. "Suck my cock real hard! Oooh, this is so good, Mom! Your mouth is wet and hot and… Oh, suck it, suck it, Mom!"

Julie was devouring her son's cock hungrily, her lips sliding up and down wetly. Although Julie's eyes were open, they rolled about and had a glazed look in them. Carol had seen that look on her sister's face many times before, usually in the back seat of a car with a boy's hand up her skirt. It meant her sister was about to come. Julie was hunching her hips now, moving as if she had a cock up her cunt, fucking it while sucking on Bobby's cock.