Mac Rebennack, a.k.a. Dr. John, first introduced Maria Muldaur to the frisky, risqué songs of New Orleans’ Blue Lu Barker. During sessions for the self-titled debut album that features Muldaur’s first national hit, “Midnight at the Oasis,” Rebennack suggested she cut “Don’t You Feel My Leg.”

Barker recorded the original version of the bawdy blues classic—co-written with Danny Barker, her larger-than-life musician husban...