"Those ads in the back of your paper. Herpes. American Pie," Jason Biggs says. "You can get rid of them for a minute, you can suppress them. You can put a little topical lotion on the American Pie franchise, but eventually, it's gonna come back." Not one to let this glowing opportunity of an STD metaphor slip away, Eddie Kaye Thomas chips in. "Just when you relax, you're like, 'Maybe we don't need to wear a condom,'" Thomas says. "Bam! Herpes!"

Turns out these actors have just as much of a wild, off-color and occasionally juvenile sense of humor as the characters who've made them famous. Biggs and Thomas both rose to prominence in 1999 with their roles in the original American Pie film – as straight man Jim Levenstein and dry sophisticate Paul Finch, respectively. The movie turned out to be a continuing boon to both their careers; they reprised their roles in 2001's American Pie 2, 2003's American Wedding and now American Reunion, which opens this weekend.

"When I first heard about it, American Pie 4, I was like 'Why don't you not do it?'" Thomas says. "We've done it. Let's not and just be happy with what we did." But his mind changed when he saw the film's script, from Harold and Kumar writers Jon Hurwitz and Hayden Schlossberg. Biggs says the story is a return to form for the franchise. "They took the franchise, I think, back to the first movie, both tonally and structurally, in a way that I think some of the other sequels were unable to do," Biggs says. "I'm proud of those films and I think they were great, but I think we got a little bit away from the original emotional core of the stories, the relationships and that kind of comedy."

American Reunion sees the original film's cast of characters coming back together in their 30s for a high school reunion. The actors say there's actually not too much difference between the high-school insecurities of the first film and the adult insecurities of this one. "The reason I think people enjoyed watching the first one is that it's about how terrifying it is to be in high school," Thomas says. "It's like, 'Oh my god, I'm a graduating virgin,' and that's the most terrifying thing possible." Biggs chips in. "And this is about how terrifying it is to be on the brink of 30, and I'm not what I thought I would be," he says.

Terrifying undercurrents aside, the Pie franchise is about over-the-top, gross-out humor. And these guys definitely have a strong sense of that, even in the midst of a PR tour. The two riff constantly, occasionally tripping over each other's words in a rush of banter. Although Thomas has that same Finch-like deadpan, in real life he takes the straight-man role, with Biggs often convulsing in chuckles as they ramble. When Thomas mentions straightforwardly that this wasn't the first time someone tried to "mount" a fourth Pie film, Biggs giggles. "I love your use of 'mount,' all the time, in this interview," he says. "We are five years old, by the way."

So how long will we be continuing to apply topical lotion to the Pie franchise? Thomas turns to another famous franchise for a precedent. "I'm serious when I ask this: How many Police Academies were there?" Thomas asks. "Eight? I think as long as there's material, they'll make it. So if Jon and Hayden can write a good American Nursing Home, I'm in." In the meantime, Biggs has grabbed his smart phone for an answer to Thomas' question; there were seven Police Academy films. "So we're just over the hump," Thomas says. "We're on our way down though. We're on the downward slide at this point." | RDW