Made popular by Roosh V, traveling author extraordinaire.
"But dude, Li Lu grew up in Cupertino."
"Doesn't matter, she was born in Guangzhou."
Text sent at 3:56AM: "Chilean flag"
Text received at 3:57AM: "Congrats fuckface, i hate you"
Girl 2: "Why is she such a flag?!"
Guy 1: "Don't know what you saw in Becka mate she is such a flag!"
Guy 2: "I know, her legs were like tree trunks."
Skaters can also be seen wearing flags. They usually wear black or white ones (although the color probably doesn't matter for them), and theirs is neatly folded into a triangular shape and only about four inches of it stick out, whereas the gangsta/rapper/rap-influenced person practically lets the whole thing hang out.
Derek: I know! I was straight flaggin'!