“A human flag is an elite bodyweight hold in which the body is statically held by the arms on a vertical object, suspended from the ground like a flag.” Quote from http://www.fitstream.com
In order to be pull off this maneuver, a person would require (1) Amazing upper body strength and (2) A core that you can crack walnuts with. It’s a sophisticated hold that also requires (3) A brain larger than a pea because one would have to find (4) A pole or anchor point that should be stable or secure enough to hold your weight.
Because without any of the above, failure is imminent. And the whole Internet is going to laugh at you.