My brother had a kind of embarrassing moment? But he played it off pretty well.
See, he bought an accordion and took it with him to school... uh, don't ask me how he lugged that thing around or why it wasn't confiscated or whatever.
Anyway, he never played before and was trying to experiment with it and figure out how the darn thing worked. So he was playing it and some other kid came up and said, "You know you're holding that upside down, neutral don't you?"
That should have been an embarrassing thing that made my brother look dumb, but instead of being flustered, he replied "I know! 8D" without missing a beat.
So sometimes, you can play off embarrassing things by acting like you meant to do it and it's just part of your humor or something.
Now, when you do things like trip up the stairs, that's not necessarily something you can play off... I just kept going as fast as I could (which was the cause of the incident in the first place gonk ) without looking back.
Just try to ignore things like that. If you make a big deal, other people will make it a big deal.