The act of embarrassing someone by making them look foolish or stupid in front of a large group of people.
Usually it is unintentional or by accident. it can either be a dick move or the person is completely overreacting
first coined in the robot chicken star wars
BJ- (to a group of females) Yeah i'm the vocal coach for the band. I taught them everything they know.
Jay- no you're not dude, aren't you a janitor?
BJ- why did you have to sandbag me in front of those girls man? i was gonna get some!
Jay-what are you talking about? what does "sandbag" even mean? they were out of your league anyway
BJ- You're a total sandbagger man...