(An excerpt)
"Helen was coming now, tossing her ass, moaning as the boy continued thrusting. He had excellent control, his hips moving at an even pace, the relentless penetration giving Helen even more pleasure.
Then finally the boy started pounding her, ramming his penis inside her vagina as his own climax approached. He cried out as he came. He muttered something Dutch as he slammed into her and spewed his fluid. Helen groaned as she took it, coming again as she felt the sperm gushing in her cunt.
Aaron came too. His sperm squirted like a geyser as he gazed at Helen's buttocks, at the boy's buttocks, at the boy's sliding penis so thick and red as it moved in and out of Helen's opening.
Later, after they rested enough to regain their sexual interest, Helen coaxed Aaron to do it to the boy, to take him like a woman. The boy was quite eager for it, kneeling on the bed and moving his hips provocatively. Aaron stood behind the boy's raised buttocks and Helen gripped Aaron's balls as he pushed his penis inside the boy's anus and started thrusting.
"Yes, it's good!" the boy groaned.
Aaron was in a daze of pleasure. The boy's ass felt marvelous, a lovely firm grip that made him tremble with joy. He kept his hands moving over the boy's hard buttocks, feeling the flesh, relishing the strangeness of it.
Helen now reached underneath the boy to take hold of his penis. "Ah, you do like it," she said with a short laugh. "You're almost ready to come." She released the boy's penis and she moved behind Aaron again. He felt her hand squeezing his testicles. Then Aaron felt her pushing a finger inside his anus and he guessed she had her thumb in there.
Helen said: "Do you like it, Aaron? Do you like doing it to the boy?"
"Yes."
"Go on, shoot it inside him. He's dying for it."
She gripped Aaron's testicles and moved her thumb at the same time. Aaron groaned and started coming, his hips pumping as he ejaculated in the boy's ass.
"Yes, that's good." Helen said with a chuckle. She gripped Aaron's balls more firmly, her thumb probing more deeply inside his rectum. "Spunk in his bottom, darling. It's good, isn't it? Isn't it lovely?"
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"Three Women" by Anonymous (1992)