“There’s a show on this Wednesday, and we don’t even know what it is,” says South Park co-creator Trey Parker in the trailer for 6 Days to Air: The Making of South Park .

That pretty much sums up the operational procedure for the makers of South Park , which has become one of television’s most culturally relevant and long-running animation series in history.

The process works just fine, according to Arthur Bradford’s revealing documentary, which offers a three-month peek inside Parker and South Park co-creator Matt Stone’s 24/7 pressure-cooker.

Well, almost.

“We don’t have any friends anymore,” Stone says in the trailer. “I wonder why.”

Bradford was granted deep access inside the profane machinery of Parker and Stone’s South Park Studios in Los Angeles. So expect some seriously foul language, as well as hilarious sequences of Standards and Practices drones working out the intricate details of how characters, say, crap into each others’ mouths.

Executive producers Stone and Parker’s award-winning series has come a long, long way since starting life as the uproarious animated short film The Spirit of Christmas back in the mid-’90s. Its triumphant 15th season bowed this April, and recent episodes show zero signs of gray hair.

“We wanted to make something that would appeal to both the hard-core fans and the casual viewers,” Bradford said in a press release. “Trey and Matt are two of the most interesting people I know, and the way they make South Park is completely fascinating and inspiring.”

6 Days to Air: The Making of South Park airs Sunday at 10 p.m./9 p.m. Central on Comedy Central.