Nobody expected Dad to come home, Dad least of all.
Lawrence had been pulling overtime at the office, trying to get a key account closed before the deadline. But when he suddenly ran out of paperwork at around 2:00, everyone realized they'd gotten done early. "Good job," the boss said. "Even better than we could have planned for. Why doesn't everyone just knock off early, and we can start the next project tomorrow?"
So Lawrence came home expecting a quiet house, a quiet cup of coffee, and maybe a quiet nap before seeing the family. Instead, he heard strange grunts and moans coming from the top of the stairs. Wait, that was definitely his son Kyle's voice. Did Kyle have a girl over? Did his weird, nerdy son even know girls existed? Something was up, he knew it. He headed for the stairs to investigate.
What he saw shocked him. There was his daughter Megan, arched over on the floor, eating out her brother Kyle. Even beyond the incest, he was shocked to see his daughter doing something so overtly sexual: she was just barely into young womanhood, and he'd always known her to be shy around anyone, especially boys.
But there she was, face-first in her brother's groin, licking and sucking furiously at Kyle's... vagina? Lawrence realized his son had a teenage girl's sleek, toned legs, meeting in what was undeniably a pussy. And as Megan bobbed up and down, aggressively tongue-fucking her brother, he realized his daughter's small, pert breasts were now enormous, mobile love apples. Against his will, he felt himself starting to get hard.
Lawrence stood watching his children fuck for what felt like hours, but might have been as long as thirty seconds, before Kyle noticed him there. Dazed by the pleasure his sister was inflicting on him, he could only smile stupidly. Then he noticed his father's visible erection. He had an idea.
*You, father, will look as you did at 16,* Kyle thought wordlessly, using his wish-granting power. *Keep a grown man's memories, but have the face and body of ripe, driven teenager.*
Lawrence didn't notice his body start to shrink. At sixteen, he was only about two inches shorter than his full adult height, so he didn't get much smaller as he de-aged, at least vertically. His first clue that he was really shrinking came when his middle-age spread disappeared, and his khakis were suddenly several inches too large. He grabbed his belt in both hands, still hypnotized by the incest happening in front of him, but also desperate not to be pantsless in front of his own children.
Kyle reached out with his brain, putting thoughts in his father's head. *Isn't Megan pretty? Look at those big, juicy tits. Megan is girlfriend material. Wow, she's in your age bracket now, isn't she? Oh, you would love to take your trouser rod and impale this pretty piece of womanhood, wouldn't you?*
Stunned by the changes, and blinded by teenage lust, Lawrence was powerless to resist the thoughts his son put in his head. He dropped his trousers and stumbled over to where his children were fucking. Megan had her perky ass in the air to minister to her brother, and her back to her father, who she didn't yet realize was even there.
Lawrence pushed his boxers down and kicked them aside. Now clad only in a dress shirt, he grabbed his pretty young daughter by her hips so he could aim. Megan let out a tiny yelp, but couldn't speak, or tear her gaze away from her brother's pussy. So when Lawrence lined up his teenage cock with his own daughter's tight slit, she could do nothing to stop what came next.
Megan whimpered, small and voiceless, when her father began to rape her from behind. The terrified, defenseless girl had her father's cock in one end of her, while the other end was buried up inside her brother. Her father started out slow and tentative, but when he realized Megan wouldn't fight back, he began stroking in and out of her, driven by Kyle's thoughts and a simple need he hadn't felt in himself for years.
Kyle ran his fingers through his sister's hair as he felt his first female orgasm building. The movements as Lawrence fucked her made Megan's tongue-fucking all the more powerful. All at once, Kyle knew it was coming. He gripped his sister's head and held her fast in his groin. Brother, sister, and father all came at once, father filling his daughter's womb with seed while brother squirted his sister's face with stinging hot girl juices.
Then, as fast as it started, it was over. The three teenagers collapsed on the floor, Lawrence on top of Megan on top of Kyle, their hair and limbs a tangle of sweaty post-sex ecstasy. Even Megan, who had been trapped and raped into sex from both ends, couldn't bring herself to escape this feeling of bliss. With one weak, limp hand, she caressed her brother's gorgeous girl thigh.
Kyle looked up at this wild, incestuous threesome he'd created. Megan had daddy sperm in her tiny teenage womb. Wouldn't it be wonderful if she got pregnant? That would be amazing. Kyle wondered if he could get pregnant too. As he reached down to pet his sister's very large breast, he wondered what he could, or should, do to his family and friends next.