Seeing Jenny's vagina brought his new adult penis to attention. "Wow, my peter is hard." Billy flicked it. Jenny couldn't take it anymore and grabbed his dick and started sucking. Billy couldn't believe what was happening. It felt so good to have this girl sucking on his willy. He soon came and the orgasm ravaged his little body and he felt greater than anything. His dick soon went flaccid as he laid back basking in the glory of his first blowjob. Jenny swallowed Billy's cum and some dripped off her little lips.
"Wow Jenny that was great." Billy noticed his dick was starting to go up again. "Let's do it again!"
"Okay Billy, this time let's stick it into my vagina."
"Otay!" Billy didn't need any guidance as he pretty much dove on the little girl and his dick soon entered Jenny's adult hole.
"Now start going up and down." directed Jenny.
Billy took the advice and started pumping up and down. Jenny, forgetting that she was a virgin, winched as Billy broke her hymen. Blood started gushing out and Billy freaked. Jenny explained that's what happens but keep going it gets better. Billy continued despite thinking Jenny needs a bandaid. Jenny started moaning which sounded completely weird coming from the voice of a five year old. They were humping like little bunnies and Jenny was getting pleased having sex for the first time. Billy never thought of sex before in his life and still didn't even know that's what it was called. As he listened to Jenny moan he thought about what his mom and dad do behind closed doors. They must have been doing what he was now doing. Why wouldn't they let him join it was fun! He continued pumping his dick into Jenny's tight cunt and soon he felt that feeling he had when Jenny blew him. Soon he orgasmed as did Jenny and loads of cum went into Jenny's womb, which happened to be adult as well. Little did Jenny know that she would be pregnant in a matter of moments.
Billy climbed off Jenny. Even though that was the greatest experience ever, he was completely exhausted. Billy thought it was time for his nap and curled up and fell asleep as his big dick laid there still covered in sex juices. Jenny couldn't believe how awesome that experience was. She thought about the amazing feelings corsing through her body and wondered how she lived five years without experiencing that. If she had grown up normally she would have to wait another 10 or so year before her first time. That brought anger to her as she felt betrayed by her parents of not knowing the joys of sex. Then that got her thinking. Maybe to punish the parents for not teaching sex to her, she would de-age her parents' genitals. That would be funny seeing her dad with a little pecker and her mom with the slit of 4 year old. Then she thought of changing many adults and changing kids to be like her and Billy.
Before she could think anymore she heard something move nearby and she panicked as her and Billy were still naked from the waste down with genitals suitable for people thrice their age!