"Lara, how much time do you have left before you can't turn back?" asked Luke.
Lara looked at her own screens, for she shared her parents' ability to perceive the world as a game. "Oh, plenty of time, Daddy. 50 minutes. This isn't an "unsafe" transformation like the one that Mommy nearly lost herself too."
But Luke knew it wasn't that simple. The longer they were like this, the less they'd WANT to turn back. He had to get them to turn back now. "I'll do it...under one condition. You turn back, immediately. And I don't mean after we have sex. I mean immediately."
"How about as soon as you're turned?" asked Lara.
Luke growled. "Fine, but then you turn back. Promise me."
Lara squealed with happiness. "Oh, I promise, Daddy!"
Lillian smiled. "I can't wait to see what a sexy incubus you make, lover. I bet your cock doubles in size."
Lara's eyes widened and she even literally drooled a little at those words.
Lillian's eyes glowed, and a magic circle appeared around the bed. She smiled at her husband as she straddled him, her opening poised above his member. "The spell will of course require sex."
Luke didn't resist as she sunk down, moaning shamelessly as she penetrated herself on his rod. He reasoned that this was his wife, so it was ok, but as he gave in and thrust up into her with abandon it served to weaken his resolve, which was of course part of the plan.
Lillian grinned. "Yeeeessss that's it lover, fuck me like the whore I am."
Luke wasn't generally too into degradation, but for some reason it turned him on right now. He thrust harder and harder into her.
Lara giggled. "Watching Daddy fuck Mommy is much better than just listening through the door."
And fuck her he did, with greater and greater savagery as his transformation began to take hold. Soon he came, but it didn't even slow him down. In fact his horniness only increased. It skyrocketed to levels he could scarcely imagine, and soon all he could think about was mating her, teaching the bitch her place. He effortlessly snapped his bonds and threw her down onto the mattress. He aimed his now gargantuan cock at her hole, vaguely aware that it wasn't normally so big, that he could feel something growing out of his head and back, but mostly only aware of his need to utterly dominate this little whore. She seemed totally willing as she wiggled her ass back and forth and moaned his name, but that barely mattered. What mattered was teaching her her place. How dare they bind him, manipulate him? He was the male, the ruler, the king.
They went so deeply into lust as they fucked that they forgot their own names, but eventually he did come down, and when he did he saw his woman panting in exhaustion, seemingly endless streams of semen pouring out of each of her holes. Good. His 15 inch long cock was stil raging hard as he loomed proudly over his conquest, and wondered if he might take her one more time for good measure. Then he heard a sound behind him, and turned to see his little girl face down on the mattress, her cute red butt and pussy raised in the air for him, spade tail raised up and out of the way. She looked back at him, wide-eyed, a little intimidated after what she'd seen, but dripping with desire all the same. He'd almost forgotten about her. But her submission was excellent. She was ready to learn her lesson too.
Then something clicked inside of him, made him hesitate. There was something...something important. The timer! Suddenly Luke was back, albeit a terribly lusty version of Luke that had no qualms about fucking his daughter, but incubus or not her safety came first. "Lara, how long on your timer?" he asked.
"um, 20 minutes?" she said. "Plenty of time, Daddy..."
"No." he said. "Turn back."
"Daaaaddyyyyy pleeease!"
"No. Do it now."
"But I don't want to be a stupid human! You were supposed to fuck me! Why does Mommy get it but not meeee?"
"Do it, or I won't fuck you."
"Wait, you'll fuck me when I'm human?"
Luke growled. "Until you can't walk straight, baby girl."
"Yay!" she cried, and quickly shifted back. But when she did, the shock of what she'd done to her parents caused her to tear up. "Mom, Dad, I'm so sorry..."
"Not yet you aren't." said Luke as he and his massive erection loomed closer to her. Lara's eyes widened. "Dad...um...maybe you should change back?" she said.
"I don't think so, slut. It's time for you to learn your lesson." But as he drew closer, the look of genuine fear on his little girl's face reached his human heart, and he stopped.
"Alright. We're changing back. Lillian, you first."
Lillian hissed in reluctance, but Luke knew how to handle her.
"That's an order, slut." he commanded, and submissively she obeyed. Then he turned back himself.
The three sat there in shock at what had transpired, and yet, they had to admit they'd enjoyed themselves...
"Soooooo..." said Lara, "I was thinking maybe I'd like something a little more sweet and tender than what Mom got?"
Her parents looked at her with exasperation. She truly was incorrigible.
"Oh come on!" said Lara. "We had a deal!"
"Lara..." began Luke, but Lillian interrupted.
"Babe, I love that you want to protect our little girl, but I think we have to face what we are. Even in human form, we're lusty beings, and honestly, what's wrong with that?"
"Lillian, I can't have sex with my own daughter..."
"Why not?"
"It's not right..."
"Says who? A bunch of religions from Earth? We're not even in that multiverse anymore."
"But..."
"Luke, you won't hurt her. You'll be sweet and loving and you'll make her day, her year, her lifetime. What's wrong with that?"
Luke considered long and hard, and had a hard time coming up with a rebuttal.
"You know I'm right." said Lillian.
"Maybe..." said Luke.
"Good. Now go show your princess how much you love her."