Professor Caterina Pizzigoni, who is adorable and Italian and sometimes has trouble with English words and concepts, shows a slide of a man holding a rooster.
Caterina: "What do you think the man is doing with the cock?"
[Scattered laughter]
Smartass in the front: "He appears to be stroking it."
[More laughter. Pause]
Caterina: "Do you know why he is stroking the cock?"
[Class explodes]