Something I noticed about 3 seconds ago about my students:
What makes them laugh with embarrassment when they ask/say it is rather different.
1st years: "How old are you?" then embarrassment and/or giggling.
2nd years: "Vagina." then usually giggling (the boys giggle, too)
3rd years: "Did you masturbate last night?" then giggling...and anticipation for answer.
Do we see where puberty leads? Do we? Do we really now?