The girls packed inside the juniors department were squealing ecstatically. Even back in the administrative corridors, where the store executives’ young daughters were cloistered, the silence of zealous expectation was deafening. Rock stars must get used this kind of welcome.

“It’s really not normal,” Pete Wentz swears later. “I think anytime it becomes normal, you’re in a dangerous position.” As bassist for quartet-of-the-moment Fall Out Boy, the pop-punk band that takes its name from a Simpsons character, Wentz has been handling the normality of “it” exponentially since the band’s first full-length CD four years ago. But his stop this autumn at Macy’s Bellevue Square to promote his clothing line, Clandestine Industries for DKNY Jeans, was a bit surreal. The hormonal yearning of the crowd threatened to be uncontrollable; Wentz had to exit the screaming sooner than planned.

“To be honest, the sound gives me anxiety,” he says, sunk now into a chair in someone’s office-turned-refuge. “What if I don’t live up to that? How do you stay ‘on’ all the time? You definitely cannot satisfy every single person. I hope they walk away with something.”

Wentz is softer in person than his reputation for high times and hard living would suggest. Safe in this room with his tagalong girlfriend, pop star Ashlee Simpson, he seems pleased with the clothing line and chatters happily about bleaching and chemical emulsions like a teenager working on a student project. He holds out a Clandestine hoodie (“The lining feels like having a puppy dog on your head”) then tries on a Clandestine leather jacket. “It looks dumb on me,” he decides. “It accentuates my shortness.”

“It’s cute, though,” Ashlee offers.

“It looks good on her,” says Wentz, nodding toward Simpson. They both look very young; either could pass for a member of the crowd clamoring for them. But the pressures of facing down his own peers with Fall Out Boy may age the 28-year-old Wentz. “I want people to be able to grow with us,” he worries. “We’re just four dudes from Chicago. We were the kids getting hit with the football in school. I don’t want to alienate any of our fan base, but to see those kids who were throwing the footballs at us in our audience now is a little bit of a mindfuck.”

It’s more than Wentz expected. “If you want to be famous and make a lot of money and not have a job that will give you a stomach ache every day,” he offers, “I can tell you a million better ways to do it.”