Briefs and Adolescence
It is hard to believe but there are a school regulation that school boys are only allowed to wear a specific underwear in Japan.
This regulation is mainly adapted to elementary school, and the underwear are white briefs.
Elementary students usually don't care whatever they wear. However they begin to be shamed wearing a white brief since they enter junior high school.
It is probably because they reached adolescence.
For the reason, you should care when your son ask you to change other underwears from white briefs.
