Pretty much means anything you want it to. Your teacher randomly gives you a pop quiz? You got memed on. You accidentally go left instead of right? Memed on. Originated solely because I started to say “get dabbed on” unironically, so I needed to think of something worse than that.
Dude, we are totally going to get memed on at the tournament this weekend.
When some one states somthing akward leading to an akward the only way to prevent it (stop it if it has already happened) is to tell the person to leave by saying "just get out"
Guy 1: dude i was jacking off and
guy 2: dude im sorry but your gonna have to leave
guy 1 walks out
guy 3: that was the bestget outmoment ive ever seen