Jimmy didn't know what to do, he was mortified that he was kissing another guy, that Bobby's hairy and sweaty skin was so close to him and that he felt so vulnerable about this. On the other hand, he truly was wondering if he was enjoying the experience, it wasn't just his lips and saliva exchanging with his little sister's babysitter, it was a whole new experience that was making him tingle in a way he didn't know he can.
The awkward one-sided kiss was now consensual and he was kissing him back. In fact, Jimmy was hugging Bobby's broad back, occasionally moving his hands down to rub Bobby's bubble butt. It was a little fuzzy but Jimmy didn't find it so disgusting. Meanwhile, Bobby was using a hand to support himself above Jimmy while he uses his free hand to rub his own dick, feeling how it gets hard and makes contact with Jimmy's.
When Jimmy felt Bobby's hard dick touching his own dick, he tried to stop but he immediately he felt a new something that changed his mind. His cock was getting hard! He can't believe it, he wasn't doing anything, his dick had decided to be hard by it's own. When both dicks were hard as rock, it was easier for Bobby to rub them at the same time. He slightly smiled after realizing that he got bigger than Jimmy, but also he can feel more of Jimmy's mushroom tip and loose foreskin. He always wondered how it feels to have one and maybe this was the closest way to know it.
"We need to stop." Jimmy managed to say between kisses but Bobby just ignored him. The side which told him this wasn't right was becoming stronger in his head. What if someone shows up? What if his sister discovered them? What if he likes this so much that he will never want to go back to be a kid? Before he has time to get answers, he managed to push Bobby away. He laid on the floor panting for a moment, his dick was throbbing with his breaths and his body was covered in so much sweat that he suspect it wasn't just his.
"You're right. I left myself go." Bobby said as he stood up, he was more experienced in sex, so it was normal he recovered faster. He extended a hand to Jimmy who accepts it and quickly stood up as well. Bobby gave him a big friendly smile while he patted Jimmy's broad back like a proud father. They now share the same age but Bobby still felt he was like a mentor for Jimmy. "That was a good experiment. We should try it again sometime."
"Yeah, but no soon." Jimmy said while he blushed a little. "Now, can I turn back to my original age?"
"Are you serious? Do you want to go back after feeling that?" Bobby said. "Do you know that your dick will shrink, do you?"
"And my body hair is going to disappear. Yeah, yeah, I know it." Jimmy said. "I just want to take a shower and then a nap. I'm really tired."
"Then, just do it."
"I'm not going to take a shower in this body!"
"Why not? It could be an interesting experience." Bobby smiled. "I'm going to tell you right now that I'm not going to turn you back into a child until tomorrow when your parents arrive."
"You must be joking. I won't fit in my pyjamas or any other of my clothes!"
"Then, you can borrow some of your father's or you can go around naked. Neither I nor your sister will care about it."
"You... just... Ahh!... Fine! I'm going to take some of my father's clothes!" Jimmy reluctantly agreed while he walked to his parents' room. "I hope dad has some new boxers because I refuse to wear a used one."