Meshell Ndegeocello is best known for her own sensuous, soulful songs, but she’s also been a bassist to the stars for years. She can be heard laying down the bottom line with some slippery funk on Madonna’s 1994 cut “I’d Rather Be Your Lover,” adding some hip-shaking low-end propulsion to John Mellencamp’s hit version of Van Morrison’s “Wild Night,” and bringing the rock ’n’ roll thunder on The Rolling Stones’ 1997 single “Saint of Me,” to name just a few examples.