Oh Shit! （やべ）

He Says:
yabe　（やべ）=oh shit!, in big trouble
Many japanese people use yabe in many situations. When we get up late, we say "yabe!!", when we send email to a wrong person, we say "yabe!!".
Yabai is the original word for that, yabe is more casual way.
And you can say yaba too. All are the same meaning.
Hiro in the TV show of Hero used to say yabai many times when he gets in big trouble(I think he uses the word even though he didn't get in big trouble).
Like Hiro,many japanese use yabai!(or yabe,yaba) when it's not a big trouble.
That's ok. It's kind of common in Japan.
You can say,"yabe!! I farted!" or something.

She Says:
It's fun to make a big deal out of something. But to be honest, if you use it in the exaggerating way, Japanese people will probably laugh at you because they think that you're using the language wrong. This isn't necessarily a bad thing though.
See, in America if somebody makes fun of your English and they're laughing at you, it's a bit malicious and they think you're stupid. We expect foreigners to speak perfect English, with no accent.
Japanese people, on the other hand, tend to think that Japanese is the hardest language that ever existed and it would be completely impossible for a foreigner to ever learn to speak properly. So when they laugh at you, it's because it's just so cute that you're trying and make such a silly little mistake.

The next word is...（くそったれ　じじ）。