The very uncomfortable sympathetic feeling experienced while you watch someone else embarrassing themselves. This feeling is often intensified when the person embarrassing themself is not aware of how embarrassing their behavior is. In this case it is more like you are feeling the embarrassment on their behalf.
George: OMG, dude...this talent show is killing me. The fat girl dancing to 'Ice, Ice, Baby'...
Dude: I know man, I know...all the wrong things are jiggling--
George: --And her dancing! Everyone is laughing and she just keeps going. It's like a trainwreck right now. I don't even want to watch!
Dude: Total vicarious embarrassment right now, man.
George: Ugh. Let me know when it's over.
Similar to the use of oh my God, as in a situation of great surprise. This is better suited for polytheists such as Hindu's, and for those who want to draw looks in public.