Not every cold open on sExY ViDeO- SEXIEST BLONDE BABE SEDUCING OLD MAN !!! feet sex tubeThe Officewas meticulously planned.

We knew that Jim popping Dwight's exercise ball at the start of the Season 2 episode, "Performance Review," was accidental. But on the 100th (!!!) episode of the Office Ladies podcast, former co-stars Jenna Fischer and Angela Kinsey revealed that the memorably goofy cold open from the Season 5 episode, "Heavy Competition," was the product of sheer exhaustion in the writers room.

You know the one, trust us. It involved cheese balls.

The cold open shows Michael, Ryan, and Pam (employees of the newly launched Michael Scott Paper Company) settling into their new office by tossing cheese balls into each other's mouths like so:

It's a brilliant yet simple introduction to an episode, but according to "Heavy Competition" writer Ryan Koh, the idea was super last-minute and involved no real thought at all. (Fans of the Office Ladies podcast may also know Koh as the writer who had a speed radar accident during "The Duel.") The idea, he says, was "most of all a product of exhaustion."

Koh explained that his first draft of the episode featured a cold open in which Ryan thought Pam had a crush on him. The writers' room ultimately decided to toss it, so they needed to think of something new. Unfortunately, everyone was too burnt out to think of a good replacement.

"At this point in the season, all the writers were really exhausted. In Season 5, as you recall, we did 28 episodes and they were shot in 10 consecutive weeks of production, then a break so Steve could do a movie, and then 18 straight weeks of production," he said. "Other shows I've been on, I've told them that there was a stretch of 18 straight weeks of production and they do not believe we did that."

The writers were mentally drained, the actors were worn out, and Koh described it as a "rough time."

"So anyway, we were all very spent and we were trying to come up with a new cold open, and it was either [writer] Aaron Shure or Paul [Lieberstein, writer/actor/co-showrunner]. They were both the guys that were really good at making something out of nothing," Koh explained. One of them said, 'I don't know. They're throwing cheeseballs at each other?' And everyone's like, 'Great. We don't have to write anything. That's awesome. OK, that's the cold open. Cheese balls. All right, next.'"

The cop-out ultimately resulted in a hilarious, genuinely impressive series of cheese ball tosses and mouth catches, which Fischer assures viewers were all real.

"I want everyone to know those are real cheese balls. We had the best time shooting this," Fischer said.

The cheese puff sequence took a full afternoon to film, but it should come as no surprise that the most demanding shot was the one where all three actors tossed cheese balls into each other's mouths. In the end, they pulled it off, and the reactions shown onscreen were genuine.

"That was the hardest one. You know that reaction that you see at the end when we finally make it?" Fischer asked. "That was real. I think you can see the look on my face. I knew I caught mine and then I had to look and see if they really caught theirs and then we were genuinely excited. That was the only time we ever got that toss correct."

The cold open was "without a doubt" one of her favorite sequences to shoot on The Office, and she feels like all that cheese ball throwing really bonded her, Steve Carell, and BJ Novak.

Be sure to listen to the full podcast to hear more behind-the-scenes stories from filming "Heavy Competition."

You can stream episodes of The Office on Peacockand follow along with the podcast every week on Earwolf, Apple Podcasts, or Stitcher.