Đán: Daddy, do you know what a vagina is?
Dad: What? A vagina?
Đán: Yes, do you know what a vagina is?
Dad: What is it?
Đán: It’s like cu (Vietnamese for penis), but only for girls.
Dad: Interesting. Where did you learn that?
Đán: From S (a girl in his class).
I was not sure if I should be laughing or shocked.