When the comedians behind the Chicago-based musical improv group Baby Wants Candy decided to throw together a spoof of Fifty Shades of Grey a few weeks before the Edinburgh Fringe Festival, they didn’t really expect it to take off. But then again, who would have thought a poorly written erotica novel would become an international sensation?

If we’re being completely honest, the success of 50 Shades! The Musical is a lot more comprehensible than its inspiration. Unlike E.L. James’ Fifty Shades trilogy, which started out as online Twilight fan fiction, 50 Shades! The Musical is a collaborative effort between a crew of super-talented writers, comedians, and musicians. And bonus: You won’t be ashamed to be caught seeing this show in public.

Head writer Al Samuels knew right off the bat that he didn’t just want to make fun of the book. “Railing on the book was too easy,” he says on the phone from his home in L.A. “And also it felt too easy to just do parody songs. And we really wanted it to be a show that someone could enjoy as a musical, because if there’s no heart to it, even if it’s a parody, we felt like it wouldn’t be a very satisfying show for us as artists or for the audience.”

Samuels decided to use a book club to frame the show. These sexually repressed housewives introduce the story of Anastasia Steele and Christian Grey, and they reappear throughout the performance. The show has evolved significantly since the original one-act production (which ended with the song “Butthole in Control”), but the writers took that same core concept and developed a full-length musical full of witty references and catchy songs.

Amber Petty, a New York-based comedian with ties to Baby Wants Candy and the Upright Citizens Brigade, has played the role of Ana since the first run. When she first heard about the show, she immediately sat down and read the books.

“It’s so interesting to me that [the books have] been so popular, just because I wouldn’t have imagined an erotica book being so popular with such a huge age range,” she says. “And then the books are a little more tame than I thought. I was really glad I did read them. It is a little more about the characters and the relationship between Ana and Christian, and the S&M stuff is not half as much as I thought there would be. I was glad to see the real story.”

In the books, Ana starts out as an awkward, virginal college student who discovers an unexpected side of herself thanks to mysterious millionaire Christian Grey. “Eventually, it’s more about her finding her own self and what she wants to do, and becoming a woman and making her own choices — even if those choices mean being dominated sexually,” she laughs. “To me what’s fun about her is … she’s very innocent and sweet and naive. So we kind of play that up in the show, and in a way she’s almost like a Disney princess, but with a totally different storyline.”

Original songs like “There’s a Hole Inside of Me,” “They Get Nasty,” and “I Don’t Make Love, I Fuck” (a real line from the book) help propel the story. Petty’s years of training as a singer are clearly evident as she belts out lines like “I’ve got sugar and tea but no cream in my cup.”

Though this is strictly an 18-and-up affair, Petty promises things don’t get too racy onstage. “It’s mostly language stuff. As far as what we do on stage, anything we do that’s sexual is really heightened and silly, so that kind of stuff, it really doesn’t make you uncomfortable,” she says. “I’m kind of prudish in my real life, and I feel like, if I’m comfortable doing all this stuff, everyone else will be totally fine.”

For now, they’re touring only in the U.S. (parody laws are more flexible here than in some other countries), and audiences have ranged from young couples to people in their 80s. One thing they all have in common: They’re crazy about the show. “I’ve done a lot of comedy shows, and I’ve never had people react so strongly to a show,” Petty says. “People are really laughing the whole time.”

Samuels suggests a few reasons for the show’s popularity. First, they handle it in such a way that it appeals to fans of the book as well as those who’ve never read it. “It’s a beloved story and characters to a lot of the audience, and they just love the story itself,” he says. “But it’s such a fine line. If you don’t treat it both with the right level of parody and the right level of respect, you’ll alienate that part of the audience. But I think we have a good balance of that.”

He adds, “We were really careful to make sure that you cared about the story of our musical. It wasn’t just, let’s make fun of how ridiculous the book is, how silly and how spoofable — and all of that stuff is definitely there — but in the books and on the show we wanted to make sure there was the core of a relationship and relationships that you care about. Otherwise it’s just sketches, it’s just cartoonish … By the end of it, you really care. Are Ana and Christian going to get together, and are the book club ladies really going to become actualized?”

There is the question of how long the show will be relevant, but although the books have been out for awhile now, the movie is still in the development stages. Samuels hopes they’ll be performing it for awhile. “I didn’t want to do a show … that would have a shelf life of six months to a year,” he says. “[I wanted to make] a musical good enough that in five years you look back and it could still be running, even it’s making fun of a phenomenon that maybe isn’t as much in the forefront of pop culture … I feel like ours could be that.”