Having reluctantly agreed to join Martin, Ryan and their cronies on the air, I take a stab at playing off the phone call, stammering that the caller is probably working off Mom's theory that you should always wear clean underwear because, if you get into an accident . . .

"You think my underwear isn't clean?" Martin snarls, dropping his shorts to prove that it is. In the process, he displays . . . well, let's just say it's the kind of locker-room thing that only a sports reporter should see.

Ryan cracks up. All I can say is, "Whoa."

And this a slow day at The Russ Martin Show.

• • • 

Since about fall 2001, Martin's 3-7 p.m. show on KLLI has continually been at or near the top of the Arbitron ratings. There have been a couple of off quarters, but more often than not, he's No. 1 in his time slot.

Even Martin says he isn't sure how this happened.

"That's been like the underlying theme for the show is that I can't really figure out what the attraction is," the 44-year-old Martin says. "If I could, then I could write a book or become a radio consultant. The only thing I can figure is . . . the show has just turned into a great big high school, and you're in somebody else's class and you just happened to stop by that day. I always liked high school, so I think it's cool."

The cast -- Martin, Ryan, producer Rob Riddlemoser, associate producer Dan O'Malley, promotions guy Clois Raborn and KLLI program director Gavin Spittle -- often refers to the show as "the treehouse." It's a boys club; girls are allowed, but they should expect to be razzed. Bosses get hassled. Rivals get ripped. Sacred cows get slaughtered. Rude noises get made.

Instead of a treehouse, though, I'm reminded more of a particular VW Bug, the one my friend Don and I cruised around in during and after high school, splitting six packs and talking about -- well, anything. We told politically incorrect jokes and spoke candidly about women, without the filtering that occurs around people who might misunderstand or misinterpret. We debated the merits of movies, TV shows and rock groups. And we gabbed about whatever else crossed our minds.

If only we had known that there was a hit radio show in it.

"I think everybody has done that at some point in their lives," Ryan says. "And they look back at those times, and they think . . . 'We used to just hang out and laugh at stupid stuff and talk about everything from religion to sex and politics to the fact that I've got an ingrown toenail.' It takes everybody back to that little moment in their lives. We're just fortunate to do it for a living."

Despite his professed surprise at the show's popularity, Martin does have some theories: It's a way women can get guys' perspectives on topics they wouldn't normally be privy to, and it's a way for guys to talk about sex, albeit in a juvenile way. And it may be a treehouse, but it's a local treehouse -- Martin is a Dallas boy who has spent his nearly 25-year broadcasting career in the area.

For fans, Martin's appeal is simple.

"[Martin] has the guts to say what everyone else is thinking but too PC to say," says Jeff Folse, a Fort Worth listener who works at a commercial real estate company in Las Colinas. "He is a 44-year-old teen-ager who lives in a fantasy world, but he has the ability to turn anything into hilarity. . . . When you first discover the show, it is kinda like driving by a bad car wreck -- you know you shouldn't look but you just have to."

• • • 

While growing up in the Pleasant Grove area of southeast Dallas, Martin says, trouble followed him -- "nothing dramatic, but there were disciplinary problems." The moment of clarity came when he was in college (he attended Eastfield College in Mesquite and did a semester at the University of North Texas).

"I had a college professor pull me in his office one time, and he said, 'Look, you're a smart kid -- why don't you pull your head out of your a- - and actually focus on things?' " And Martin began to focus.

He landed a part-time gig at a Greenville station in 1980, but radio wasn't his big dream. He wanted to be on TV, and he saw radio as a steppingstone. It was: He met Ryan when they worked at sister stations KAAM-AM and KAFM-FM in the early '80s, and they hit it off, talking about just about anything. Then Ryan had an inspiration.

"I said, 'What if we took this and did a television show?' " Ryan says. "And he looked at me like I was nuts and went, 'What?' And I said, 'Why don't we just take this stuff we do, and put it on video?' And the light went on."

So did the show, Hot Tkts, which aired from 1989 to 1993 on KDAF/Channel 33 even though it was originally given a three-week window (it aired one more year, as Hot TV, on KTXA/Channel 21). The show basically consisted of the two traveling around the Metroplex, covering venues and events; when Martin was on camera, Ryan did the filming, and vice versa. According to Martin, it had about 500,000 viewers weekly.

Shortly before the show ended, Martin returned to one of his old radio stations, KEGL/97.1 FM "The Eagle." At the time, the Eagle aired Howard Stern in the mornings, but in 1997, then-owner Nationwide Insurance canceled Stern, saying that, although he had the No. 1 show in Fort Worth-Dallas, nobody would buy ads on it because of the raunchy content.

Stern fans threatened to boycott the Eagle. Martin, who was the midday jock at the time, was put in the unenviable position of taking over the morning slot. But he brought the ratings back up.

"It appeared that we got a lot of Stern's audience back as well as our audience just from our own niche," he says. "Maybe there were no other options. Maybe there was nobody else in the market and they went, 'Well, it's this guy or nothing.' Maybe I won by default."

Ryan, meanwhile, had been working at country stations KPLX and KSCS until a vocal-cord infection caused him to lose his voice for two years. He spent much of that time producing TV commercials and doing other behind-the-scenes work. Around Christmas 1999, he regained his voice and got back into radio at a fortuitous time.

Infinity Broadcasting was getting ready to flip its country station, KYNG, to a "hot talk" format and wanted Martin, who was in contract renegotiations with the Eagle. Because the "noncompete" clause in Martin's Eagle contract had expired, he was available to jump ship -- and he did, signing on KYNG's talk format in early April 2000. He invited Ryan to join him and took members of his Eagle crew (including Dan Lewis, the show's original producer, who now has a show of his own on KMSR/990 AM) along with him. They held the morning spot till January 2001, when KYNG (now KLLI) brought Stern back to town. The Russ Martin Show moved to afternoons -- and that's when it really began taking off.

With Stern set to go to Sirius Satellite Radio in 2006, Martin would seem to be the likely replacement in the morning slot. After all, he did it before. But he says he won't do it again.

"I'll quit before I go back to mornings," he says. "It's just too much of a compromise of your lifestyle. You have to get up at 3, 3:30 in the morning . . . you're back in bed by 9, 10 o'clock at night. . . . I only did it for four years, and I couldn't stand it."

• • • 

You get a sense of Martin's love of nostalgia soon after you walk into his large but not opulent home, which he shares with his Chihuahua, Abbey. Old TV Guides are scattered around the house, including, appropriately enough, one featuring WKRP in Cincinnati on the cover. Next to the front door is a small room that's been turned into a bar; in the garage are the Batmobile and a Mach 5.

The guy likes muscle cars, but he says he doesn't exactly live life in the fast lane.

He says he gets up about 8 a.m., works at his computer till about noon to prepare for the show, has lunch, does some more preparation till about 2 p.m., takes a shower and goes to work (the show seldom sounds like it takes that much preparation, which is just the way Martin wants it). After the show, he works out, goes back home and is in bed fairly early.

"I don't really do a whole lot of anything," he says. "Can't remember the last time I went to a concert. The free time I have on the weekends, I catch up on house stuff, yardwork, whatever. And then by the time that's caught up, it's Monday again. I'm pretty much of a shut-in."

Yet his adventures with women provide frequent show fodder.

"Immediately, when it comes up on the air, it becomes a problem: 'I didn't realize that you were going to talk about that,' " Martin says, adding that when he mentions to women in his life that he's not using their real names, they reply that their friends know whom he's talking about. "So the radio show has probably ruined three or four relationships in the past."

But then, Martin talks about a lot of things you're not supposed to talk about on the air, and they don't always have to do with sex. Many radio personalities wouldn't think of mentioning a rival jock on the air, but Martin has no problem praising the ones he likes -- or, more often, slamming the ones he doesn't.

"Radio people are just so plastic," he says. "And it's funny that they think that they're further up the entertainment chain than we really are. I don't like 'em."

Kidd Kraddick, the longtime Dallas-based personality whose morning show airs on KHKS/106.1 FM "KISS-FM," is a frequent Martin target. Kraddick, who worked at the Eagle when Martin was there, declined to comment for this story other than to say, "I don't think anything would be served by that." The Fitz, the former KRBV/100.3 FM "Wild 100" morning DJ, was another frequent target (Wild -- now Jack-FM -- and KLLI are in the same building). Fitz didn't respond to a request for comment.

In fact, though Martin has his critics, attempts to get one to talk on the record for this story were unsuccessful (one simply said he deals with his distaste for Martin by not listening). Perhaps that's because there is a perception that Martin has a lot of clout within Infinity's six-station cluster here, which Martin finds amusing.

"It makes me laugh every time somebody gets fired, and then they go back, and they blame me, and they say, 'Well, he didn't like me, he got me fired,' " he says. "Could you absolutely be that retarded? . . . There's nothing I can do to get anybody fired. I can say I don't like 'em and not promote the show, but if the show's successful, whoever it is, no one jock is gonna get them terminated."

If you want to find slams of Martin, all you have to do is occasionally check out Radio-Info.com's Dallas message board; anonymous posters there have criticized him as an overrated egotist. But Martin is quick to say that the show isn't just him -- it's all the guys involved with it. And he doesn't believe his ego's as big as some others' in the industry.

"There are a lot of people in radio, after they've been around for a while, they say, 'You know what -- my ratings are great, obviously anything I say is gonna be entertaining,' " he says. "That's not the case. I go in every day assuming that everybody hates me and hope for the best."

And -- perhaps because he has played fill-in for Stern twice now, perhaps because of the sexual and racial political incorrectness of his show -- he gets slammed as a Stern clone. Although he doesn't believe that he is, he does acknowledge some Stern influence.

"Stern has been like a heat shield for radio for a long time," he adds. "He would test the waters, and I think a lot of the other jocks would follow suit and go, 'Stern got away with this, obviously this is OK.' A lot of them won't give him credit for it. Which is absurd. It's very egotistical to think that everything I'm doing now is because of me. Well, Stern set the standard for a lot of us." (Martin, too, has taken calls from pro-decency crusaders, who usually wind up being mocked by him.)

Mark Davis, who hosts his own talk show on WBAP/820 AM, says he's a fan of Martin's show and says that there is a Stern comparison to make -- but it's not about show content.

"People make the mistake of saying that Howard is popular because of the vulgarity and the strippers and stuff like that," Davis says. "That's absolute nonsense. Howard is popular because of the chemistry that he has shared over the years with [his cast]. People listen and care about what this cast of characters thinks about things. This is something that Russ has now achieved. And it's very hard."

• • • 

But Martin has a soft side, which comes out in his work with two charities: Operation Kindness, a no-kill animal shelter, and the Russ Martin Show Listeners Foundation, which supports the families of police officers and firefighters killed in the line of duty (since 9-11, Martin has led an annual parade honoring military troops and emergency workers).

"That came from my dad," Martin says of his concern for police and firefighters. "When I was a kid . . . I didn't really get the concept of why would these people go and help other people they didn't know. You'll hear me use the word 'selfless' a lot. That's where it came from.

"The animals thing, I don't know," he adds. "It's really hard to go to the shelter and see those dogs and not want to do something. I'll turn it around: 'How could you not?' "

Martin has even teared up on the air, sometimes when talking about a fallen police officer, other times for sillier reasons (shortly before Ryan underwent his recent surgery, the cast read "eulogies" for him -- and Martin got verklempt when reading his). Everett Newton, the lawyer who appears on Martin's show twice a week, said it best when he told Martin: "Beneath your veneer of [jerkiness] lurks a mushy center."

"It gets in the way of being a jerk," Martin says. "But I think a lot of times, if you keep the mush in check, and it only comes out every so often, I think it carries more of an impact."

Is Martin a jerk? In an off-air interview, he doesn't seem like it; he's a gracious host and an affable subject. On the air, though, he can be nerve-racking to talk to, because he's quick and mischievous and you can never be prepared for what's going to come out of his mouth.

"Everything on the air obviously is a characterization of our real lives." he says. "In everybody's character, they have their jerky side, they have their compassionate side. On the air, everything is just amplified."

Maybe that's another part of the appeal -- in Martin's compassionate jerk, listeners can see both sides of themselves. But KLUV/98.7 FM's Ron Chapman -- whose morning oldies show is the antithesis of Martin's -- says the jerkiness is exaggerated.

"If that's supposed to be his reputation, that's supposed to be his image, I'm sorry to be the guy that's breaking the mold for him," says Chapman, who, like Martin, works under the Infinity umbrella. "He's OK. He's a hard worker, and within the company, we all know that he delivers and that he works his a- - off to have it done."