The more Jon thought of it, the more he realized that it might not be the best idea to fully rope his teacher into his perverted fantasy. But he still wanted to at least indulge them. So the best way to do it is to spend the night together and then undo everything before tomorrow morning. Jon picked up the wishing rock and got ready to wish.
"Alright. I wish that Ms. Wattson would invite me to her house for a (long) one night stand. She finds me very sexually attractive, but isn't looking for anything other than a fun night banging hips (for now at least). Nobody finds this invitation unusual or unethical and nobody calls us out on spending the night together." The stone glowed before a burst of energy flew out throughout the world. Once the light faded, his landline began to ring. Before Jon could get to it, his mother picked it up instead.
"Hello, Gibson residence.... Yes?... Uh huh... Right... Jon?!" His mother called up.
"Y-Yeah?" He responded.
"Your teacher, Ms. Wattson wants to know if you'd be interested in dinner with her?"
"Yeah... Sure." He responds. "What time?"
"What time?" His mother asked over the phone. "About 7."
"Sure. Tell her I'll be there."
"He'll be there. Alright. Yeah, thank you for calling." She says before hanging up the phone. "Well, looks like you're going to be spending the night with her as well." His mother said casually before returning to what she was doing.
"Alright..." Jon said, sheepishly before rushing back to his room. "Okay, nobody finds anything wrong with this... Good..." He mutters as he picks up the stone again. "Now to make it so that I can have some fun... I wish that while I was at her house, sometime before 8:30 and lasting until 5 o'clock tomorrow morning, Ms. Wattson and I would spontaneously merge together into a single body with two heads, half hers, half mine, and we can only control our half of the body. Our heads would be just far apart so that we could look at one another in the eye but still close enough to kiss, our limbs and torso length would be balanced out so that we're not lopsided as we walk, and our genitals would be fully functional and arranged in such a way that we could easily have sex with ourselves." The stone glowed for a minute before bursting out energy again.
"Okay, now I wish that rather than be horrified, disgusted, or angry at becoming merged together, Ms. Wattson was only shocked and bewildered by it at first, but once we got our bearings with the situation, we both find being stuck together to be so absurdly erotic that we end up fucking until the early hours of the morning. If we don't fall asleep by the time 5 o'clock comes, then we instantly fall asleep at 5 and our bodies will separate like they're supposed to. Also, we both find that sex while conjoined is loads better than sex in separate bodies." The stone glowed and granted his wish.
"Finally, I wish that Ms. Wattson will never find out that I was the one that merged us together unless I explicitly tell her. Even if she finds out about the rock and that it can do that to us, she'll never make the connection that I did it this time." With that final wish granted, Jon put the stone in a spot where it would be safe until tomorrow morning and went to go take a shower, excited for his night ahead...