IRS is an acronym.
It stands for:
This acronym is fairly new, and cropped up because of the recent Nuclear disasters happening over in Japan.
Used when referring to someone who is obsessed in some way with radiation.
The acronym also stands for a government group that is despised and hated throughout the whole country. Those taxes that you pay every month? Yeah, that's these guys.
"What a freakin' IRS - stop talking about radiation, nobody's listening anyway!"
Guy 1: "Okay, so when the radiation from Japan-"
Guy 2: "Ah, not Ah-GAIN!!"
Guy 1: "-we'll walk to the other side of the country and-"
Guy 2: "Shut up. Shut up, shut up, shut up, shut up!!! I've had it up to here with your talk about radiation! Shut UP!! You're a freakin' IRS!!"
Guy 1: "Well, geez, there's no need for THAT kind of language..."