One of the constant mind games I play with my students is how I grant them permission to go to the restroom. Students usually ask to be excused by saying, "Teacher, Me Bathroom!"
Whenever they do this, I say, "Oh, hello Bathroom. Is that your new ‘English’ name? Say hello to ‘Bathroom’ everyone!" The students get very embarrassed and figure out the problem. If not, I just call them "Bathroom" for the rest of the day in class. They don’t ask as much anymore, and they ask their friends the proper grammar before asking me the next time. Educational shaming. It’s all in good fun, and the students don’t take it too seriously.
Today, one of the girls in class asked me about going to the restroom. I got to jokingly call her ‘Bathroom’ for a few minutes until she got her expression correct, then I let her out of class. She returned from the bathroom with a paper cup of water. This also gets on my nerves. Lots of students also get called "Water" in class because they want a drink at the water fountain but don’t know the proper words to ask permission. Bringing back a water cup to class means that everyone is going to start asking me if they can go have a drink.
I asked the girl, "Did you go to the bathroom, or to the water machine."
She said, "I went to the bathroom."
I followed up by asking, "Then, is that toilet water you are drinking? I didn’t give you permission to drink water from the fountain. Why are you drinking toilet water?"
The girl got very embarrassed again and denied she did anything wrong. It was a joke, so I let her know that next time she would have to ask permission for both and not bring the cup back into class. She agreed and I went back to calling her by her "English" name. No harm, no foul.