Thirteen years old! He gaped at the face that he remembered from just 4 years ago - Derrick had been a late bloomer, with puberty not even starting to show until he was nearly 14. Then he'd gone from the class shrimp to being one of the taller boys in his class over the next few years.
Hebe grinned. "You did insist on my treatment. I'm afraid that at your age, even a few years makes a big difference. Are you satisfied, or would you like more?"
Shaking his head, Derrick felt his face as he continued to stare at his reflection. "Uh, no. Thanks, anyway." Thirteen was plenty young enough. "At least it's just for two weeks."
She nodded. "If that's what you want. Anything else?"
He gave her a puzzled look. "What else do you do?"
Shrugging, Hebe said "Oh, I can change coloring, race, physique, maturity, and of course, make you even younger."
"Isn't maturity the same as aging?"
The girl shook her head. "Not at all. For example..." She slipped her hand into the water and startled Derrick by gently stroking his nub of a penis. He felt a flush of heat and then stared as the prepubescent nub pushed out several inches, and small testicles pushed out underneath. "There. A year's head start."
He rubbed himself, happy to find he was sensitive there again. "So, I'm 14 now?"
"No, silly." She chuckled. "I only make people younger. But you are now more sexually mature at 13 than you were before. I take it you approve?"
Derrick reddened a bit, but nodded. "Uh, could you do more? I mean, if I can stay like this for the vacation, it would be fun to..." He trailed off, embarrassed again.
"Oh, a well endowed male of any age will find plenty of sport here." Hebe started to masturbate him, each caress of her fingers causing his sexual equipment to enlarge slightly. Derrick shifted and started to pant as he pounded erect, arching back as he stiffened. There was an unfamiliar pulling sensation, and he looked back down to find that he now had a foreskin stretched tight over a penis that was larger than he'd had when he came in! The flush of heat was all through his body now, but sexual pleasure filled his mind. He came suddenly with a surprisingly large ejaculation, gasping in orgasm. When it was over, he was shocked by the immense shaft and testicles resting between his skinny legs. At least nine inches long and two thick, the penis has a thick foreskin that hung loosely over the head as it retracted, and his testicles looked like a smooth sack holding two ping-pong balls!
More than just his sexual parts had changed. His face was now that of a young teen with a wisp of hair on his upper lip, and his body and limbs were elongated. Derrick touched a few red spots - acne. He still looked like a 13 year old, just one who was a lot more developed than he had been before.
Hebe looked him over approvingly. "Too bad you are giving this up after two weeks. If you kept it, you'd be extremely impressive by the time you were 17 again." She grinned. "Not that you are not impressive now."
Derrick flushed slightly, aware that he was substantially better endowed than any of the kids he'd seen at high school, much less Middle School. Still... "Is there a way I could keep this? After vacation?"
She nodded. "If you want, this can be made real. As in an alteration to your reality. If I do that, though, it will be a permanent change that will be reflected in your life and the world around you. You will be 13 when you go back, and everyone will remember you as being 13. That is, of course, assuming you do not accept an other changes while you are here."
Derrick looked down at himself and thought about being back in Middle School like this.