Caltech biology - short essay about humor

Please check if there are any grammatical errors... errrr i'm so pressed for time!!!

At that moment, the brave student folded up his trousers and slowly stretched his right leg toward the teacher without any words. After a few seconds, the teacher and all the people who were watching this burst into laughter.

This is my story of an event occurred when I was taking the biology class in high school. Oh, yes, that daring student was me, and since then, for a long time, my classmates and biology teacher called me "a boy with shapely legs."

Thanks in advance

I'm a little confused. Was the class supposed to be observing your muscles?