I was teaching a class last week on the colors and patterns of clothes. We got to the word "paisley," which is pretty tricky to pronounce, so we worked on it together a few times.
One student kept saying it in an exaggerated katakana way and his friends were laughing "PIE-ZUREE?! PIE-ZUREE!?!"
Then I realized that what he was yelling with all his might was not an honest struggle to achieve natural pronunciation, but 「パイズリ」, which is Japanese slang meaning "titty fuck"
I had to lol at this. It was the first time i've totally lost it due to a dirty joke in class. Freakin' hilarious.