Muffs leader Kim Shattuck repeated a mantra to herself just before her band's Tuesday-night performance at Hollywood's Amoeba Music.
"I said, 'I'm not going to swear. I'm not going to swear. There's a bunch of kids here.'"
Then the Muffs took the stage: "Boom," said Shattuck. "I drop the f-bomb."
The next words out of her mouth: "I'm sorry, Eleanor!"
"My niece is Eleanor," the singer explained, "and I want to be a good aunt."
The world around Shattuck may be more grown-up since the Muffs' self-titled debut in 1993 — marriage and family concerns are more top of mind than punk-rock rowdiness — but Shattuck's modus operandi is still react first, worry about it later.
Certainly the pop group is still rough with punk edges. Some of the band's angriest songs in its two-decade history are on its new release, "Whoop Dee Doo," the group's first album in 10 years.
"Choppy rhythm, plus fast," Shattuck said to describe her approach to the opening song on the album, released this week on Fullerton's Burger Records. "Whoop Dee Doo" largely stays on offense from there.
"I don't care what I'm saying half the time," she sings through gritted teeth at the album's midpoint. And while girl-group harmonies may temper the mood, Shattuck keeps the listener guessing by adding, "Are you scared?"
None of this aggressiveness directly addresses her recent firing from the Pixies, the reunited alt-rock forebears with whom she toured for three months in late 2013 after founding bassist Kim Deal left the band that summer.
But getting axed was good news for Muffs fans, as "Whoop Dee Doo" was essentially completed in 2011 and put on hold for what could have been a potential year-and-a-half tour with the Pixies.
Looking back, Shattuck noted that there were red flags from the start. Shattuck said she was practicing with the band on handshake and verbal agreements for six months prior to the announcement that Deal was leaving the Pixies.
"So, really, from January to July, I was secretly in the Pixies," she said.
"I was practicing and working really hard with them, without getting paid a dime. Nothing. No money. … I've learned from that ordeal. I should have been paid. I didn't know how it worked, and I wasn't sure what I could ask for. My bad. Oh, well. I should have pressed for some payment. Live and learn."
Asked for comment, a Pixies spokeswoman passed along a recent interview with Pixies leader Frank Black in Magnet magazine, where Black talks of Shattuck's unkempt approach not fitting in with the group. "She's very West Coast, she's very extrovert," he said. "We're very East Coast, very introvert."
Extrovert can sometimes be an understatement.
When Shattuck was reached by phone at her Glendale home Wednesday evening she copped to sporting only a towel as she was in the midst of getting ready for that night's Dodger game.
She spoke frankly about a variety of topics, be it her personal life or the potentially creepy guy who's neighbors with her mom (he's the subject of the new album's "Weird Boy Next Door").
Another confession: When the Muffs join a host of other female-led garage and punk bands for Saturday's all-day Burger-A-Go-Go fest at Santa Ana's Observatory, it will return Shattuck to a venue where she was once barred from performing. She said she raised the ire of the space's former operators when the Muffs appeared at a sister venue as openers for Cheap Trick.
Shattuck took offense to the fact that patrons were dining in front of her.
"I got really crabby about it, so I started messing with people's food," she said. "I went onto tables and straddled people's food, pretending I was going to do something with it. I didn't! But I got on my knees and knocked dishes over. I was obnoxious. We were banned."
Maturity didn't figure too heavily into the conversation.
The Muffs, with a consistent lineup of drummer Roy McDonald and bassist Ronnie Barnett since the early to mid-'90s, still place a heavy emphasis on humor and brevity.
Whenever more grown-up concerns figured into a song, Shattuck said it happened by accident.
"Like You Don't See Me" starts out full of snotty, frayed riffs and frustrated pining, with the occasional yell thrown in for good measure.
But Shattuck gradually turns the focus on herself as the melody opens up to allow for some old-fashioned rock 'n' roll innocence. It's a song about the compromises of marriage, though it wasn't intended as such.
"I was bummed about feeling ignored by my husband, but during the course of the song I realized, 'No wonder he ignores me. I kind of deserve it.' I do things that put him off. There's two sides to every story," she said.
"Maybe he's ignoring me because I'm being weird or saying stuff that's not cool. I didn't realize this until I listened to the song later."
If longtime fans think that sounds too deep, don't fret; there are a couple songs where Shattuck plays out some revenge fantasies with violence.
While pop-punk may often be associated with teenage rebellion, Shattuck doesn't concern herself with writing to her age.
"When people get older, they get bitter or get cute," she said. "We want to be the cute old man on the corner feeding the pigeons. Or, do you want to be the bitter old man who's screaming, 'Kids these days!'"
There may be a little bit of both in the Muffs.
"I've actually said get off my grass to people before," she added after a pause.
"They were skateboarding on my grass! Get your skateboard off my grass. That's not for you to play with."
The Muffs at Burger-a-Go-Go!
Where: The Observatory, 3503 S. Harbor Blvd., Santa Ana
When: 2 p.m. Saturday