Is it normal for a boy to try on his mother's underwear?
When I was a boy (long ago!), girdle ads were still regularly on TV. At around the age of 12, I eventually tried on my mother's panty girdle. This became a habit. At the age of around 14/15 I even worked up the courage one day to wear an all-in-one girdle to school. This didn't become a habit, as I spent the day in sheer terror at the thought of being caught! I've never been able to kick this recurring urge.
I used to fantasise that I was being forced to wear it - it was easier that way than to face up to the fact I was doing it because I enjoyed it.