I haven't had an embarrassing moment at school (at least not one I can remember), but I suck at presentations.
...
A girl in my class wanted to open the windows and asked everyone if they felt hot too. She asked me, "Nick are you hot?" I took the chance and said "Yes, I'm really hot." Was lol.
EDIT: Oh no wait I remember one now. During phys ed my dingaling kept getting out my boxers via the flap and causing an inconvenience. No it was still in my gym shorts but it was still uncomfortable. No one noticed though.