Source, philly.com, Suzette Parmley

Men will be entering the new-fly zone, starting around mid-October at King of Prussia Mall.

That’s when the online men’s underwear retailer Tommy John plans to start selling its underwear there, in choosing the mall as the location of its first physical store.

The debut is part of a growing trend of online men’s apparel retailers opening stores — think Bonobos and Untuckit — and making “experiential retailing” the new normal.

Tommy John is promising guys of all ages an undershirt that stays tucked and boxer briefs that don’t ride up, meaning no more wedgies. The firm also promises the “most comfortable underwear they’ve ever worn” or they’ll exchange it or give refunds.

Tommy John is the brainchild of Thomas John Patterson, who nine years ago was a frustrated medical-device salesman for Covidien, now Medtronic, in San Diego. He says he had a hard time finding an undershirt that stayed tucked in, didn’t yellow as quickly, and was comfortable.

Patterson said he found a fabric he liked in the Los Angeles garment district, sketched an undershirt with a longer, tapered design, and asked his dry cleaner to sew it up for him. The prototype inspired him, so he made 15 more, sending them to family and friends. They loved it and requested he make more.

With that, Tommy John was born in 2008.

He got his first big break a year later when he secured a meeting with a buyer and launched in Neiman Marcus. Patterson insisted on sending the product to the buyer’s husband and male colleagues before the meeting, so she could get feedback.

Patterson said that when he arrived, she tripled the original order, green-lighting the brand to be sold in 15 Neiman stores instead of five.

“We grew exponentially from there,” he said this week. “Talking about men’s underwear was one of those taboo things. There wasn’t a whole lot of innovation or rethinking since the early 1900s.

“Over the last few years it has moved from an afterthought to more of a considered purchase, and that’s why we are taking this next step.”

Men are also taking ownership of their underwear. Women bought 65 percent of men’s underwear in 2008, but only 35 percent by 2016, the NPD Group found.

Patterson said Tommy John grew online by 200 percent from 2014 to 2016, while its wholesale presence doubled this year alone. As head of a privately held company, Patterson declined to disclose revenues.

“We’ve always had an interest in owning our brand and giving our customers a personal experience where they can touch and feel the product and try it on,” Patterson said. The brand is sold in Nordstrom, Men’s Wearhouse, Bloomingdale’s, and Dillard’s, as well as in men’s shops, golf pro shops, and tennis clubs.

The underwear costs $27 to $48 a pair. The brand’s best seller is a $34 second skin boxer brief. Besides the no-wedgie guarantee, the boxer briefs come with a stay-put waistband and a horizontal fly vs. a vertical one, making them ambidextrous — both for left- and righthanders.

The 1,100-square-foot Tommy John store is still under construction in the mall’s luxury level, where it sits next to the Art of Shaving store.

“The migration of online players to physical stores is only natural,” said Craig Johnson of Customer Growth Partners, a retail consultant. “The stores become a virtual billboard to build awareness and attract customers.”

Said Christa Hart, senior managing director at FTI Consulting: “These businesses are increasingly realizing the importance of creating relationships with their customers in the physical world to gain confidence in the brand. And the A/A+ mall is a natural place for this to occur,” she continued, referring to malls such as King of Prussia.

Tommy John entered into an email campaign in fall 2016 with Untuckit, an online menswear retailer that sells shirts to be worn untucked. Untuckit just opened a 1,850-square-foot store at 1611 Walnut St.

King of Prussia Mall “is a testing lab to see what our customers respond to,” Patterson said. “We are taking a know-nothing approach since retail is changing at such a rapid velocity.”

Patterson said he drew from his past as a medical-device salesman in marketing his underwear.

“At the end of the day, guys want simplicity.”