You, for your part, had spent a lot of the day milling about the house, trying to get yourself out of of neutral as far as the supposed "body switching machine" in the shed, and in that time you'd consumed quite a bit of soda; no two ways about it, you need the bathroom. But when you open the door, you're greeted with the sight of your mother, stark naked and touching herself.
"The hell, Mom?!" you exclaim, turning around and making to exit the door.
"Oh, Kyle!" she replies. "What's wrong?"
"What's wro--what do you mean, what's wrong, why didn't you lock the door?!" Actually...why didn't she lock the door? And something about her tone bothers you, like she genuinely doesn't understand your reaction. Could she have...?
"Huh? Why would I lock the door?"
"Obviously so that no one would see you...doing that!" It's all but confirmed in your mind what's going on, but you feel the need to make a hundred percent certain. "Look, just, put your clothes back on, I need to show you something in the shed!"
Your 'mother' shrugs, you see, looking out the corner of your eye as not to catch more than you want to see. You notice she picks up her bra and gives it a good, long look before just dropping it in the sink and throwing her top back on, which clinches it in your mind. Your bathroom needs forgotten, you lead this impostor back out to the shed and look at the machine.
"Hm? Kyle, what's this thing?" asks your 'mom'.
"Well, there was a note that came with it that says it's for switching people's bodies," you say slowly.
"Oh...so it wasn't a sorceror..."
This catches you off-guard. "Sorceror? What're you talking about? You didn't switch with my mom on purpose?"
"Nuh-uh," says the unwitting impostor with a shake of the head.
"Wait, then who are you?" you ask.
"Marky!" says your mother's body openly.
Marky? Your little brother? Well, that would explain the scene in the bathroom earlier. You're not really sure you want him in Mom's position, although it could be interesting enough, especially with your mom stuck in his body in return. But then again, you have in front of you a perfect opportunity to use the machine for yourself - the question is, do you want to? Maybe it'd be more worth it to get brownie points with Mom...