This, unfortunately, has made me remember two very funny incidents when I was about 10/11 but is about mixed toilets.
I was visiting Bruge in Belgium with my parents and needed the loo, my dad had already been and warned my mum that they were mixed.
I was given the eyes straight ahead.... instruction and my mother pushed me in the back as she did so she slipped into some men who were using the urinals. My banana skin humour made me laugh so much I had to dive into a cubicle. When I came out and went back to our table my dad was cleaning her up with "Quickies", tiny wet wipes in a blue box.
On another holiday in Munich, the toilets were mixed and you had to pay an attendant for entry one woman in our party kept saying no so the attendant waited until she was in and then locked the door from the outside. Her husband who luckily was also in had to pay the extra to get her released.'
Yet again I got a lecture and a slap about laughing at inappropriate things and I',m laughing as I type this.
Being serious though when I taught loos were really difficult when you did school visits if you did not have men teachers with you. You had to count the little boys in and out, all the time hovering around the entrance to the men's loos.