Go-go music is the soundtrack of Washington, D.C. Despite a four-decade history and a few national hits like “Da Butt,” by Experience Unlimited (E.U.), and “Shake Your Thang,” by Salt-N-Pepa with E.U.

Halfway through an amazingly disjointed version of “Fading Fast,” the reunited Go-Go’s abruptly stopped the music and tried to figure out what was going on. “Did I (expletive) up?” vocalist Belinda ...