Phrase used to make fun of a dude when he is excessively showing off, while not realizing how lame he actually looks. Walking around with that extra swagger, giving that look on his face like he is "so cool."
He must actually think that he is THE SHIT, but everyone else knows how cheesy he really is.
Use with a sarcastic tone towards said bro. For added effect, repeat phrase until said 'bro' knows the joke's on him.