"I like the process of getting really excited about an idea on Thursday or Friday," Stone said, "and then there's a whole drama to the week: We jump into it, then on Saturday we go, 'Hmmmm. I don't know about this idea.' And you start questioning it."
"But you don't have a choice," Parker interjects.
"You're trapped!" Stone agreed.
The process - propelled by sophisticated computer software, endearingly raw animation and an abundance of adrenaline - clearly works.
After all these years, South Park has lost none of its edge, its scathing truthfulness or aversion to good manners. Nor has it lost the funniness with which it views the world through the eyes of Stan, Kyle, Kenny and Cartman, four bratty, perpetually bundled-up youngsters in an unhinged Colorado cartoon town.
Typically, each episode of the show, for all its focus on naughty behaviour and potty humour, crystallises into an overarching parable, with a cut-the-crap, common sense sort of moral expressed by the kids that usually boils down to some version of "do the right thing".
But that's just a happy byproduct, said Stone and Parker. South Park isn't trying to preach.
"We definitely started a few episodes where we wanted to make some point about something that's making us mad," Stone said, "and I don't think those were good episodes. We like the process much better of like, 'Here's a cool story, and let's let the characters do what's funny.' By the end, the theme kind of reveals itself, and it's sometimes the opposite of what you kind of thought it was going to say."
"Because it's South Park, we're championing the idea of not taking things so seriously," says Parker, "not being super-hardcore this way or super-hardcore that way. It's a comedy cartoon!"
"South Park's main message is: 'We're all stupid, isn't that great!"' says Stone.
"Not, 'Hey, you're all stupid,"' says Parker, "but, 'Hey, we're all stupid."'
"We're the stupidest!" chimes in Stone.
LOWDOWN
What and when: South Park series "15B" starts Comedy Central, Monday, 8.30pm preceded by doco 6 Days To Air: The Making Of South Park at 7.30pm
- AAP