A little partner-swapping.

"You two are so fucking nasty," said Robin, echoing his cousin's thoughts, and suggesting that his boyish behavior might be more of a pose than Robb had realized.

Lysa turned, frowning at her son. "Now, Sweetrobin," she declared chidingly, "that is a very naughty thing to say! Especially to your dear aunt Cat! You must make it up to her immediately!" She thought it over for a moment. "Take that giant cock of yours, and shove it down her throat!"

Sweetrobin smiled, and pulled his dick out of his mother's box. Turning, he pushed it against Catelyn's face, and rubbed it a few times, smearing her with her sister's juices. Robb grabbed her by her hair, and gave her a sharp yank. Catelyn gasped, and as she did so, Robin shoved his dick in her mouth. Robb watched as his cousin began to facefuck his mother, the boiling lust in his veins growing ever hotter.
"Oh, yes, baby," hissed Lysa. "Fuck her mouth with your cock! Fuck it hard!"

Robb pulled out of his mother with a groan, and then shoved his own member in Lysa's mouth. He was in the end unsurprised at how eagerly she took it down her throat, licking and sucking at it. Robb took the opportunity to feel up his aunt's big tits, which were as soft and heavy as he'd imagined, all while making her gag on his giant prick. For a long while, he and his cousin simply enjoyed the attentions of their aunts' wet mouths on their dicks. Then, Robb began to spread Lysa's thighs, and toyed with her
hot cunt...