My girlfriend is a grade 6 teacher. A while back, she was taking a sex-ed class, and was attempting to teach the class the proper terms for certain anatomical parts. She'd get them all to say the word out loud, without snickering or embarrassment.
One girl in particular was having a lot of trouble with the word "vagina." She tried and tried, and then eventually said, "Aw, c'mon Miss ****, why can't we just call it a cunt?"
I wouldn't even know where to begin...