Perhaps the funniest moment in Tour de Pharmacy, Andy Samberg’s new cycling mockumentary for HBO, has nothing to do with sports at all.

The comedy special, which premiered on Saturday, depicts a 1982 Tour de France in which nearly every cyclist was doping, including those played by Samberg, Orlando Bloom, Freddie Highmore, Daveed Diggs and John Cena. (This is Samberg and writer Murray Miller’s second sports mockumentary for HBO; the first, 2015’s 7 Days in Hell, was about a marathon tennis match.) But early on, the program includes a fake—and definitely NSFW—1981 Finnish commercial for the fictional KultaBank, which was introducing credit cards for the first time.

In the spot, a husband retrieves a container of milk from the refrigerator and spills it on the floor, which makes his wife angry. They have abruptly relocated to the bedroom for the next scene, which finds him under the covers performing oral sex, as she happily drinks a glass of milk. The commercial concludes with this head-scratching slogan: “KultaBank: Why pay now, when you can pay later?”

Tour de Pharmacy’s narrator, Jon Hamm, then explains that the spot’s “disciplinary cunnilingus did not do its job explaining credit cards to the people of Finland,” particularly the head of the International Cycling Union (played by Kevin Bacon), who ended up with nearly $16 million in credit card debt after just three months and informs all 170 Tour de France riders that he won’t drug-test anyone who pays him $50,000. (Nearly every athlete takes him up on the offer.)

The racy yet hilarious spot was inspired by the months that writer and executive producer Miller spent in Copenhagen, Denmark, working with Danish comedian Casper Christensen.

“I was constantly shocked by the bus ads that would drive by. There would just be bare breasts and dish soap. Since I can’t read the language, I’d be like, ‘What’s going on?’” Miller told Adweek. “I always thought that the Scandinavian’s comfort with sexuality in their advertising was so funny.”

After deciding early on that Bacon’s character would be in debt, “I realized that credit cards actually did come out in 1981 in Scandinavia,” said Miller, who also recalled a Dutch commercial that involved accidental cunnilingus (yes, really!), “and suddenly something for gold pops up, like the lowest rates in gold. So I was like, ‘OK, something with cunnilingus for credit cards sounds right.’”

In fact, Hamm’s “disciplinary cunnilingus” line was the first one from the Tour de Pharmacy script that Miller texted to Samberg.

“I was 20 pages into the script, and I hadn’t sent him anything yet. Then I wrote that line, and I was like, ‘Bingo! I’m nailing this!’” said Miller, laughing, who noted the KultaBank commercial isn’t much different from the real ones. “From my time in Scandinavia, it doesn’t feel that crazy,” he said. “I wonder how well the commercial will play in that part of the world. Will they watch it and go: Maybe that’s a real commercial?”

While the bit is relatively brief, it initially clocked in at eight minutes. “I enjoyed the tangents we went on in the last one, 7 Days in Hell, so this one I really was like, I’m going to push these tangents to a crazy limit and see if—somebody called it ‘the rake effect’ from The Simpsons —will work: where something is funny, and then it goes on so long it’s not funny anymore, and then it comes back around to being funny,” Miller said.

But when they watched the eight-minute sequence, “we went, ‘This is just insane. This makes you feel crazy watching it,’” said Miller.

What remains is a Cycling Enthusiast magazine editor in chief played by Maya Rudolph explaining why the KultaBank ad is so confusing: “First of all, why is going down on his wife payment for this guy? And what’s he paying for, spilling the milk?”

Dolph Lundgren, who plays the modern-day version of Cena’s cyclist, adds, “We saw him spill the milk, so why is she drinking the milk in the very next scene?”

While the spot initially was conceived as a Dutch ad and named a real Dutch bank, Miller switched the origin to Finland at the request of HBO’s legal department and made up the bank’s name.

The husband in the spot is wearing Miller’s actual glasses. “His outfit didn’t look complete, so the art director was like, ‘I wish he had some glasses,’” said Miller. The costumer didn’t have any on hand, so Miller volunteered his own.

Miller had wanted to include fake commercials in 7 Days in Hell and even wrote several of them, but the production didn’t have the time or the budget to include them. If he and Samberg make additional sports mockumentaries for HBO, Miller hopes to include more branding and athlete sponsorship gags, he said, “because they are fun to write.”