How many times did other teenagers or parents see you in your underwear.
As a teenager, I only remember it once, when I was 14 and a high school freshman.
Did you get to see other teenagers in their underwear.
No.
Did you ever see someone that you knew from your school. How did they react... if you had briefs on, was your package showing?
I never saw someone I knew in their underwear, but when I was 14, being weighed in just my briefs, I saw a boy and his mom being led into an adjacent exam room. I didn't recognize him at the time, but from the looks of him, I assumed he was a senior in high school. As I was a late bloomer, I had no bulge in my briefs at all, but I think he was the more embarrassed one, despite him being fully clothed.
In retrospect, I know why. One, we went to the same school, and he may have recognized me. He was only a grade ahead, so he was 15 or 16. Two, based on my own exams at that pediatrician through age 16, I know how his exam was about to go -- he would have to take off everything except his briefs for his own walk with the nurse to the hallway scale.
Unlike me, he was not a late bloomer, so his newly developed penis and testicles would be bulging in his tighty whities which we all wore at my school in 1990, at least based on my gym class locker room. During the exam, the doctor would be very sure he pulled down the boy's tighty whities twice, once lying on the table, and again standing on the floor, in a way to ensure the mom saw exactly how well her son's penis and testicles were developing. Not sure if this was reserved just for late bloomers like me, but he may have had to say when his penis started ejaculating semen, and whether it was from nocturnal emissions or masturbation.
I guess 14-year-old, late-bloomer me being weighed in my briefs really did have less reason to be embarrassed than he did.