Playing a male stripper in his new film Magic Mike, the actor, 32, embraced all that was necessary to prepare for the role – from working out three hours a day and sticking to strict dairy- and gluten-free diet, to rubbing on self-tanner every morning and waxing his legs.
"It was the most painful thing I'll ever do," he tells PEOPLE in this week's issue. "And it's something I'll never do again."
Costarring Matthew McConaughey, Alex Pettyfer and Joe Manganiello, the film was inspired by Tatum's own nine-month stint as an 18-year-old dancer at an all-male revue in Tampa.
"I enjoyed the performing part of dancing but I didn't really love taking my clothes off," he says. "It was fun while it lasted."
Perfecting their dance routines together for the film "was a little bit embarrassing at times," says the actor. One scene in particular called for Tatum – clad only in a G-string – to reverse straddle a woman lying down on the floor.
"That was one of our choreographers," he says with a laugh. "She knew what was coming but I kept certain things from her because I didn't want her to freak out."
At home, Tatum prefers to just lounge around (fully clothed) with his wife of three years, actress Jenna Dewan, whom he met on their '06 film, Step Up, and their two dogs, Lulu and Meeka.
So what does Dewan think of her husband's moves in the movie? "She loves it; she thinks it's hilarious," Tatum says. "You know, she married an ex-stripper."
For more of Tatum's interview – including his thoughts on starting a family – and photos from his childhood, pick up this week's issue of PEOPLE, on newsstands now