When “Prophets of Funk” opens at the Joyce Theater, Dorfman himself is the torch-bearer: the first mover we see. At first we are distracted by glitzy bell bottoms, afro-wigs and fringed vests, swept up in familiar sequences of ponies, grapevines, and snappy step-touch footwork. As if at a party suspended in time, we tap our foot to the familiar tunes and smile at the performers dancing together. It’s not all laymen’s steps– moments of line dancing are fluidly integrated with smooth turns, drops, and balances à la modern dance. Dorfman’s choreography calls for technique, theatricality, rhythm and charm. Video footage of the band is projected on the back screen and Sly himself is present (played by Raja Kelly). He has everyone in the palm of his hand.