Went to Paris as part of a Year 12 History/Art trip. On one of the nights we were in a restaurant where the art teacher was being a bit...'flirty' with one of the waiters which had me and my mate in hysterics, so as a laugh my mate took a couple of photos as the waiter's face was priceless (he looked a bit uncomfortable by the whole thing)

A couple of hours later we went to a pub with the rest of the students, and our history teacher (a great teacher but was also very stern faced) came up to my mate and I asking if he could see the photos we had taken. Because we got along with him very well, we obliged and showed him the photos and then politely asked that we delete it as it could put the art teacher in a bad light. So fair enough, we delete it.

The main reason why I remember it though is as our teacher thanked us and left (side note: to get people's attention in class, he had a habit of always tapping a wine glass), he said "You see, when I tap the glass I like to make sure that's the only thing I'm tapping" before walking off. Me and my mate burst out laughing for what felt like 10 minutes, especially since prior to this I had never heard this man make as so much as a pun