What is the most embarrassing thing that happened to you in school?

What I still regard as the most embarrassing experience of my life - at school, or since - was the medical I had when I started Grammar School aged 11. Parents were invited but very few bothered to attend - except my mother. The doctor was a female - quite rare in the early 1960s - and, incidentally, the mother of one of my classmates. I was stripped to my underpants for most of the examination..... until the fateful moment. I can't remember, in retrospect whether it was she (the doctor) who pulled them down or instructed me to; what I do remember is blushing fit to burn as she palpated my scrotum - I was a late developer - sporting a stonking erection as the doctor and my mother blithely talked about adolescent boys, puberty, and awkwardness over nudity. That was the last time my mother ever saw me naked!