He lifted up the back of Karen's gown and shoved his hand between her legs. She moaned softly and ground her pussy eagerly down on his hand. Her slit was scorchingly hot and very wet, soaking his hand in an instant. Bill grinned in the darkness.
Karen leaned dizzily against his chest, her whole body aflame with lust. She wanted to do wild dirty things, and she didn't give a shit what the rest of the world might think. She slipped her hand inside the fly of his pajamas and grabbed his dick, pulling it out so she could play with it.
"Yeah, baby, frig me," Bill whispered eagerly.
"Play with me, too," Karen whimpered.
Bill's fingers tickled through her wet swollen snatch, and then she felt him grasping her hot aroused clit between his thumb and forefinger. He began to knead the fat little button, and she almost fainted with pleasure.
"Yes, darling, yes," she gasped, "keep doing that… It feels so good, Bill…"
She curled her fingers around his bloated stiff cock and began to pump it. Bill shook with pleasure. "Yeah, that's what I want," he whispered. "Pump my dick, baby…"
All the while they kept their eyes on the kids, their excitement reinforced and magnified by watching the handsome young brother and sister fucking dog-style. The kids were clearly having as much fun as their parents, humping away furiously, howling and gasping their pleasure. Mark's cock dripped with Stacy's hot pussy juice, and both kids were flushed and grinning.
"Get it in farther, Mark," Stacy howled, "deeper…"
"I'm up to my nuts already," Mark laughed. "I can't get any deeper."
"Oh, shit," Stacy whined.
She thrust her saucy little ass even higher into the air, allowing her brother to penetrate all the way to her tender womb. He battered her, fucked her roughly, but she got off on the weird combination of pleasure and pain.
Nobody could fuck like her handsome big brother. Mark was right, they should have thought of this long ago. Stacy joyfully tightened her strong young cunt muscles around his firm young prick, squeezing him, tugging him ever deeper into her insatiable, boiling box.
"Oh, wow, that's great, Sis," Mark whined. "Your cunt's so fuckin' tight… Oh, man, you're squeezing me… Far out…"
He'd had some beautiful and exciting women in his young life, but none of them could ball like his baby sister. He'd never fucked a cunt so exquisitely tight and muscular and gripping. He pounded her mercilessly, ramming his thick hard meat against her womb, knowing she loved it.
"Fuck, fuck, fuck," Stacy chanted, "fuck me, big brother."
"You bet I will," Mark gasped. "I love your cunt, little, sister…"
The dirtier the kids' talk became, the more it aroused Karen and Bill. They swayed against each other, frigging each other furiously, trying to stifle their excited cries. Karen's hand flew up and down the stiff length of her husband's cock, Bill tugged and kneaded her soaked, throbbing clit. They hadn't been so hot for each other in years.
"Oh, God, Bill," Karen gasped, "I can't stand it another second. You've got to fuck me."
She dropped to her knees in the hallway, her slippery little clit escaping his hold. She wantonly threw her filmy nightgown up over her creamy round ass and opened her legs wide for him, adopting the posture of a bitch in heat. Even in the shadows Bill could see the bright trickle of cream from his wife's swollen hair-fringed cunt.
He quickly dropped his pajama bottoms down to his ankles and sank to his knees behind her. His cock weaved heavily, lewdly, in front of him, dripping hot juice. He seized Karen's trembling hips and feverishly maneuvered his swollen meat around in her slippery wet pussy.
At last he found her oozing steamy cunt mouth and eagerly split it with the huge knobby head of his cock. He thrust into her hard, penetrating her eager wet twat in one brutal thrust.
"Ooooo!" Karen howled.
She felt Bill's wonderfully long thick cock stuffing her hungry cunt. It felt marvelous. Bill moaned loudly as he worked his stiff meat up to her womb. They began to fuck like it was going to be rationed, fast and hard and furiously.
"Yes, darling, YES," Karen whined. "Oh, God, I love it…"
"You're so fucking hot in there," Bill sighed. "I want you, Karen."
Still they kept watching the kids. It increased their own excitement. Mark's slim butt was flying now, flashing whitely as he balled his squealing little sister.
Mark thought he heard a strange noise from the hall, but he was cool enough not to glance that way. He kept on fucking Stacy as if nothing had happened, but presently he took a peek out of the corner of his eye.
He couldn't believe what he saw, so he looked again. Far out – Bill and Karen were out there watching them, so turned on that they'd started to fuck, too. Mark suppressed a snort of amusement. He could pretty much figure out what had happened.
"Stacy," he gasped, "Put your legs out straight. I wanta lie down on you."
His sister obeyed, always ready to experiment, but she didn't like the results. Mark's cock didn't get far into her this way.
"Hey, Mark," she complained, "this is no good. I want…"
"I know," he interrupted, whispering into her ear. "I just wanted to tell you something. Now, don't turn you head. Just take a peek into the hall."
Stacy obeyed, then stifled a giggle. "Oh, wow," she whispered to her brother, "too much. I bet they heard us and came to stop us, and then…"
"Yeah," Mark chuckled, "I bet that's how it was. Anyhow, Sis, we've got them right where we want them. If you see what I mean."
"Yeah," Stacy said wickedly, "I see what you mean. So bring me off, brother, and then we'll have some fun with them."
"Right on," said Mark.
He raised himself to his knees again and started balling Stacy harder then ever. The hot friction made both kids howl with pleasure. In moments he felt his little sister's cunt gripping him like a vise, and Stacy screeched as a giant climax rocked her body.
"Come in me, Mark," she howled, "come in meeee…"
Mark was more than ready to do so. They'd been balling for at least a half hour. He gasped as he shot his jism into his little sister's nipping box for the very first time. Dammit, she was a sweet piece of ass. He'd get back to her, but now he and Stacy had some very important business to take care of.
They rolled apart, panting, and Mark reached up and switched on the overhead light – brightly illuminating both the bedroom and the hall.
Bill and Karen were caught in the glare of the light, stunned. They held quite still, Bill crouching over Karen, his cock thrust deep into her. They started at the kids.
Holding hands and grinning broadly, Mark and Stacy climbed off the bed and walked over to their new parents.
"Wow, Stacy," said the leering boy, "will you look at this? Uncle Bill and Aunt Karen are balling right here in the hall."
"Too much," said Stacy, smirking. "Why would they wanta do that?"
Bill groaned and drew his long stiff prick out of Karen's hot dripping box. Blushing furiously, he and Karen got to their feet and made feeble attempts to cover their crotches with their hands.
"Well, uh, this can be explained," Bill said lamely. "We don't want to talk about it right now, though. It's very late, and you kids ought to be asleep. In the morning…"
Mark and Stacy burst into loud laughter.
"Aw, come off it, Uncle Bill," said Mark. "Quit bullshitting us."
"Mark, your language!" Karen gasped.
"But that's what it is," Mark replied, "a load of bullshit. You guys are trying to pretend that nothing happened. But Stacy and I saw you, balling right here in the hall and watching us. Can you explain why that was happening?"