I had a teacher who was also a catholic priest. He was explaining the students about his vowels, including chastity vowels. One student didn't seem to be very convinced.
Teacher: "What's the matter, don't you believe I never had sex?"
Student: "Of course I don't! Not even a little!"
On a biology class the teacher was showing a drawing in a book to explain the female anatomy. She was pointing at things and explaining it, but something seemed to be wrong. Some students were amused and others a bit confused about her explanations. She took a better look about it and: "Oh, I'm sorry, this one is a penetration..."