Think of Chicago, and no doubt retired porn star Bree Olson and a certain sexual act come to mind.

No?

The new billboard at Clark and Ontario featuring Olson www.adultfyi.com/read.php?ID=57533 and the caption ­­— “Because the best job is a b–w job” — was specifically tailored for Chicago, say the brains behind the message, the hook-up dating website ArrangementFinders.com. Olson gained mainstream fame as one of Charlie Sheen’s “goddesses.”

“We specifically picked Chicago for this website,” said A.J. Perkins, in charge of marketing for the Toronto-based company [Avid life Media, who also run the website, AshleyMadison.com].

The marketing folks were thinking about the high unemployment rate in the city when they came up with the catchy slogan, Perkins said. Part of the lewd phrase on the billboard is blurred out.

“We wanted to come up with a billboard that had some sort of play on the word, ‘jobs,’” Perkins said.

For those who might find the billboard offensive, Perkins explains: “I can see that opinion on it, but with something like that, it speaks to a certain audience. It speaks to men and women who aren’t looking for a traditional relationship.”

The billboard is apparently having its intended effect.

About 1,300 Chicagoans had signed up for the dating service on Feb. 5. On Feb. 12, the same day the billboard went up, another 1,900 people in the city signed up, Perkins said.

Mayor Rahm Emanuel was taken aback — and appeared somewhat dumbfounded when asked about the racy billboard after Wednesday’s City Council meeting.

“You are a living example of why people should not have either smartphones or technology,” the mayor told a local television reporter who was holding up a picture of the racy billboard on his cellphone.

Emanuel laughed uncomfortably when asked whether the message on the billboard was an appropriate one or met his standards for Chicago.

“Obviously, it’s not one I share,” he said. “Look, we have a First Amendment. You usually operate under it. There are certain things you say I don’t think [are] appropriate also. But that said, I’m not gonna respond to that because I haven’t seen it. You’re just reading it to me. But we do have a First Amendment, and I’ve got to take a look into it.”

Told that he might turn red from embarrassment when he does see the billboard, Emanuel replied, “I might. But it will be for other reasons — not that.”