John Waters turns 80 this year. Mosswood Meltdown, the gloriously disreputable Oakland punk festival he has hosted since its inception, turned 12.

Somehow, neither shows much interest in acting its age.

Every July, a few thousand devotees descend on Mosswood Park for a weekend that feels equal parts punk festival, comedy show and a John Waters cabaret extravaganza. Waters emcees every act on both stages (this year’s lineup included Iggy Pop, Bikini Kill, Pavement and Fred Armisen and Carrie Brownstein’s Ramones tribute band, The Return of Jackie and Judy), introducing them with the sort of filthy one-liners that have become as much a part of the weekend as the music itself. This year, for example, he anointed Pavement “the cock and balls of indie rock.”

Waters has become the festival’s unofficial patron saint. Standing behind increasingly absurd podiums — a fake game-show lectern one minute, an elegant dinner table with a dead rat as the centerpiece the next — he writes every introduction himself, testing material that often finds its way into his touring stage shows months later.

Between introductions, The Hollywood Reporter caught up with the Pope of Trash backstage to talk about turning 80, writing jokes every morning and why he’d still rather spend an evening in a dive bar than at the Folsom Street Fair.