^ Why do you keep calling him Brain? It's Brian.

:
Anyways, I think the situation that was really happening was funny enough.

But for the sake of the caption, let's pretend Brian is showing Stewie fanfic "Cupcakes."
Stewie: Okay wait, so what is this now?
Brian: Just watch.
Stewie: Why are we taping my reaction?
Brian: Jus-just watch.
(video starts) Stewie: Okay..they're lesbians, clearly. I dunno... I dunno what else... Wait. Wait. Wai-- Wh-wh-what? Wha..what?! No..! No...! Agh... Agghh! Aggghhh! Agghh, what is wrong with you?! Oh, my God! Agh! Aggh! Oh, I'm never gonna be able to eat cupcakes agai-oh my God! Agh! Agh..! Oh my God! Agghh...! Oh, that is disgusting! Oh my God!