The world's oldest teen-ager didn't have his first rock 'n' roll hit until he was 45 . . . and that was 20 years ago.

So why is Rufus Thomas still working up a sweat by Walking the Dog and doing the Funky Chicken and the Breakdown in the Georgia Avenue nightclub known as the Penthouse? "Hey," says the man who wrote the songs that accompanied some of the most ecstatic dances of a generation in motion. "I'm a goodie, but I'm not an oldie."

His solid body looks about 45; his little hop steps and attitude are strictly 35. "I'm 65." Thomas pauses, for emphasis. "Not 'years old,' just 65. You only retire when you get old. I'm not old."

When Rufus Thomas was born, America entered the "Great War." Thomas, growing up in Memphis, Tenn., decided to have a Great Time, instead. It took him only six years to find his feet. "In grade school, I was a frog hopping around on the stage," he recalls in a gravelly-growly voice sweetened by an utterly disarming smile. So, since a Funky Penguin followed the Funky Chicken, how come no Funky Frog? "I don't know if I could get down there and do the frog," Thomas laughs heartily. "The legs wouldn't last too long."

Doing has been the constant in Thomas' long-lasting career. He started out as a carnival comic in the early '30s, first giving his feet free rein in the dying days of tap-dancing. "I learned the hard way," he says proudly, "in the dust, on the porch, up and down the steps." For 11 years, he and comic partner Robert (Bones) Crouch hosted an amateur night on Memphis' legendary Beale Street, showcasing unknown young talents like B.B. King, Bobby (Blue) Bland and Johnny Ace. When King left his deejay job in Memphis, Thomas took over his "Sepia Swing Club" spot. Among those who tuned in faithfully--Booker T. Jones, Al Jackson Jr. and Steve Cropper, who would later define the sassy Memphis sound as the MG's.

Thomas established his rock 'n' roll roots in 1953 with "Bearcat," billed as "The Answer to 'Hound Dog,' " Willie Mae Thornton's No. 1 R&B hit of the time. "Bearcat" was the first moneymaker for a struggling young producer named Sam Phillips and his black-artist label, Sun. A year later, Phillips discovered a wild white boy named Presley, followed by guys named Perkins, Cash and Lewis. End of phase one for Rufus Thomas, who was smart enough to hold onto his day job at a local textile mill from 1941 to 1963.

In 1960, Thomas talked a brand-new record company into recording " 'Cause I Love You" with his 17-year-old daughter, Carla. It sold 30,000 copies and was the first moneymaker for what soonbecame Stax, a funky southern version of Motown. A year later, Carla began her own string of hits with "Gee Whiz (Look at His Eyes)". It became Stax's first gold record; Carla soon dropped out of graduate studies at Howard University to reign as Queen of Memphis Soul after recording an album with Otis Redding. Carla, who just returned from a European tour, is part of the show at the Penthouse.

"In 1963, Carla showed me a new dance," says the father. "But she didn't do it the way it ended up when it was called the Dirty Dog," he adds quickly. Soon after, in a Tennessee bar, Rufus Thomas got carried away by an "exotic" dancer in a tight leather outfit. Egged on by her erotic performance, he started calling out changes to his band, started sputtering new, instructional, lyrics. Voila , "The Dog" was born and begat "Walking the Dog" which begat "Can Your Monkey Do the Dog."

"The Dog" became one more dance sensation rockin' the nation, but it also turned some noses blue. "In some areas, people were getting arrested for doing it so vulgar," Thomas chortles. "They got all down on the floor . . . Had I been the judge, I would have put them in jail, too."

Instead, he came up with more songs inspired by the dances he encountered while touring--the Push and Pull, the Breakdown, and of course, the Funky Chicken in 1969. Thomas, who still lives in Memphis and recently registered--reluctantly--for Social Security, looks ready to go another 20 years, to become the Eubie Blake of rock. He looks to a cause for such longevity. "I don't drink. I don't smoke. No drugs." His face lights up. "I'm just a natural, like when you throw seven the first time."

The Show

Thursday at midnight, when most grandfather types were safely tucked in bed, Rufus Thomas strutted out onto the Penthouse stage, bright yellow cape draped over an outrageous yellow suit, knickers almost meeting laced-up white boots. For more than an hour, he socked it to the audience in undiluted doses of blues, "soul country" and Memphis funk. When Thomas jumped off the stage to work the audience on an extended blues, some of the women had to be restrained.

Thomas showed his wide-ranging roots, not only in song, but in the flow of risque' jokes and between-songs patter. Clockwork, the house band working behind him, looked on in amazement as Thomas pushed and pulled the lyrics to his own classics ("Breakdown" and "Walking the Dog") like a 20-year-old discovering The Beat for the first time. Like sandpaper, his voice wore down restraints and left behind a swirling surface of rhythmic energy.

Carla Thomas followed with a set that confirmed her own classic funk voice, one that lies between the gruff grit of blues and the melismatic exhilaration of gospel. It wasn't surprising that her most affecting moments came in a medley tribute to Ben E. King, Sam Cooke, Jerry Butler and Otis Redding, all of whom came out of gospel backgrounds. Like her father, Carla Thomas manages to please and rouse at the same time.