WILL PENDARVIS PREPS Jason Ellis's studio guests by warning them about the host. They show up thinking they're stars who deserve star treatment, but Ellis—he's not really, he doesn't quite … well, his guests have been known to cry.

On this Tuesday afternoon in September, it's Greg Hetson sitting on the short couch that serves as the green room at Faction Radio's studio, in Los Angeles. Pendarvis sits about four feet away at his cramped desk. Skateboards signed by Tony Hawk, Kevin Staab, Tony Alva, and other greats adorn the walls and rafters. Hetson, 46, is one of the founding members of the pioneering punk band Circle Jerks. He wears black geek glasses and looks smart and confident. But, thinks Pendarvis, he doesn't know Ellis. Ellis is a 36-year-old pro skateboarder, but that only hints at who he can be on the air. What if Ellis asks Hetson to punch him? It could happen. Or what if he tells Hetson his music sucks? Ellis frequently introduces a song by saying he hates it.

Pendarvis considers this while sipping from a liter of Mountain Dew. As the operations manager of Faction, channel 28 on Sirius Satellite Radio, he's responsible for a revolving cast of athlete DJs, including, in the past year, a core group consisting of Ellis, Tony Hawk, freestyle skier Jonny Moseley, and Jackass star Bam Margera. Because satellite radio is not subject to FCC decency standards, Pendarvis doesn't technically have to be concerned with anything the guys say. But, still, warning Ellis's guests seems like the right thing to do.

Pendarvis swings his chair toward Hetson, clasps his hands before him, and says, very slowly, "You know, this probably isn't going to be a normal interview."

Pendarvis always talks slowly. He's 40 and from Bayou La Batre, Alabama. He grew up with a thick accent but has made a point of losing it. He has spiky blond hair, cool-blue eyes, and a wide face.

"Ellis isn't really a musicologist," says Pendarvis.

Hetson nods, laughs. "Sure, of course."

"He might not know anything about your bands at all," says Pendarvis.

They both glance to Pendarvis's left, where, six feet away, Ellis is jabbering in his box of soundproof glass. His nickname is "Ellis-Mate," because he's from Australia. He's wearing a trucker's cap and track pants, as always. He has blue eyes, and there's reddish stubble around his chin. His arms are huge.

Ellis is talking to a guest named Kat Von D, the star of LA Ink, a Learning Channel reality show about running a tattoo parlor. A few minutes ago, Ellis made her cry while giving her a hard time about her ex-boyfriend, Jackass star Steve-O. Still, for Ellis, this is relatively polite. When Penthouse Pet Krista Ayne comes on later in the fall, he won't even introduce himself. He'll just ask her if he can see her "cookie." Then he'll pull his pants down.