Atlanta-based bluesman Chick Willis's career dates back to the 50s when he toured with Chuck Willis, the flamboyant, turban-clad "King of the Stroll." Chick carries on his cousin's show-stopping ways, peppering his act with outrageous double entendres and ribald tales of infidelity and hilarious romantic misadventure ("I don't love my baby / I tell you the reason why / She filled my pants full of Red Devil lye!"). "Stoop Down Mama," his best-known number, is a scabrous bit of signifying that allows him to single out audience members: "See that man, he's long and tall / Bet he ain't got no stoop-down at all! / See that woman, she's big and fat / Bet her stoop-down ain't no bigger than that!" Willis's sputtering, intense guitar work complements his fiery aggressiveness and rough-edged vocal delivery, and there's a good-humored affability to him that keeps his humor from getting nasty. Willis's versatility is as noteworthy as his showmanship: he delivers ballads ("You're Gonna Miss Me") in a husky voice that's rich in nuance--an exquisite fusion of bitterness and melancholy. Friday and Saturday, Rosa's, 3420 W. Armitage; 342-0452.