Oh I have an answer for this one lol. We had this lit teacher in school, she was british, super skinny, blonde, beautiful...

But she'd do this weird thing every time in class, she'd sit at the edge of her desk, at the corner and would do a motion like she was scratching her asshole with the edge of the table.

I remember everybody in school talking about it and telling our parents at the beginning of the year, but they didn't believe us until it was time for them to go talk to the teachers and they saw it for themselves, because she'd do the same in front of them!

She was a running joke in school and to this day when we I meet my classmates we still remember her and her secret ass scratching technique.