I was babysitting for my friend's two daughters, Paula (6) and Rose (3). Paula had made a house on the living room floor and wanted to give me a tour. An eclectic pile of toys and furniture was piled up in the middle of the room: chairs, blankets, a toy chest, a tricycle, and a massive stuffed frog sitting upright in the middle of it all.
"This is the door... this is the swimming pool... this is where Mommy and Daddy sleep... and this is the bathroom," she said, pointing at the frog.
"The water comes out of here," she said, indicating his mouth.
"You turn the water off here," she said, touching his right hand.
"And this is how you flush the toilet," she whispered, holding up his left hand.
In his lap was a large green plastic 'bowl,' which was actually the shell off of some kind of massive turtle. To make her laugh and, well, because I'm quite immature, I sat in this makeshift potty (fully dressed, natch) and, using my mouth, made a massive PFFFFFFFFFFFFTTTTTH sound, imitating a fart or a rather intense case of diarrhea.
Her eyes widened, as if she couldn't believe that a grown man would be so silly. She just stared at me in disbelief. So of course I did it again. She started giggling and saying, "Noooooo!" We both got a good laugh out of that one and then went into the kitchen for a juice box.
About ten minutes later, I heard a sound from the living room. It was basically a higher-pitched version of the mouth squirt that I had done earlier. I walked into the room and could not believe what I was seeing.
Rose, the younger sister, had been on the couch the whole time we were in there before, sucking her thumb -- and obviously taking it all in. Now she sat, pants around her ankles, in the bowl. And I heard the sound again. And her mouth was closed. And her face was red. I couldn't tell if she was about to start laughing or crying, but I immediately picked her up and was almost knocked off of my feet by the stench. "Rose, what are you doing?? Why did you do that??"
But how mad could I be? After all, I had encouraged her in my own inimitable way.
I took her into the bathroom and wiped her. When I got back to the living room, Paula was crying and yelling that Rose had pooped in her house.
I took the bowl into the backyard. Shit! The hoses had been disconnected for the winter and the pipes shut off. I found an old towel on the workbench in the garage and wiped out the liquid baby waste. I then brought it back into the bathtub and rinsed it out and tried to disinfect it.
I'm sure Paula told her parents, but I can only hope to God that she didn't tell them about my little "demonstration" beforehand.