"My pussy is getting hot," she whispered.

"Of course it is, darling," Marla said softly. "It should. I mean, seeing your brother's cock swell, get hard, should make your cunt nice and wet. I know it does mine."

Bob lay and watched them. He was shaking with excitement, hoping one of them would take his cock into her mouth again. His mother's mouth felt different from her cunt, or his sister's cunt. He didn't know what the difference was, but he liked it. He liked the way his mother's tongue wiggled and stroked his cock.

But Marla knew what the difference was between a cunt and a mouth.

"Guys like Bob love to be sucked, Sally," she said, closing her fist about her son's cock and jerking up and down a few times, then pushing her hand back to his balls. "They love to be sucked more than fucking, sometimes. A girl can do a lot more with her mouth than she can with her cunt if she really enjoys sucking cock, honey. A girl can use her tongue and lips on a cock in a way she can never use her cunt."

Sally kept staring at her brother's cock.

"He's getting very hard, honey," Marla said. Sally's hand moved to Bob's cock, her hot fingers closing about it. She pumped his prick slowly, gripping it tightly Marla kept playing with her son's balls, encouraging her daughter. She moved her face close and snaked her tongue out to lick woes the piss-hole of her sets cock while her daughter jacked it. She tasted the seeping juices, and mooned softly. Marla pulled her fist back, and dress her hot tongue up and down the shaft of her son's cock.

"Lick it that way," she urged her daughter. Sally moved her face close warily, and pushed her wet tongue from her mouth. She probed at her brother's cock gingerly, barely touching his cock shaft. Marla watched, amused by Sally. She had sucked her cunt so eagerly before, delving her tongue deeply, smearing her face into the hairy wetness, yet now she seemed worded about taking a hard cock into her mouth. There were many girls who would eagerly lick a cunt, but refuse to suck a cock. Marla knew that, though she was not one of them. There were just as many women who would suck a cock off, but refuse to lick a pussy. And she wasn't one of those, either.