It is an ironic twist on Fox News's disgraceful characterization of Barack Obama's fist pound with his wife as a "terrorist fist jab" after Obama clinched the nomination for the Democratic presidential candidacy.
Bro 2: "Naw, man, I just sit around and play video games all day."
Bro 1: "Haha, me too, bro! Terrorist fist pound!!"
(They pound their fists together.)