In the latter portion of their recording career, The Cramps seemed to lose their calibration of the giddy perversities that propelled their best music. There’s a distinction to be drawn between being in on the joke, winking, even drooling, and being the joke itself. Songs like “Bikini Girls with Machine Guns” (1990) or “I Wanna Get in Your Pants” (1991) reduced the band’s fascination for the demented kitsch of American pop culture to kitsch itself, repetitions of gestures that were empty in the first place. You can forget what a feral, fearsome force the Cramps were, as the 1970s spilled into the 1980s like fluid from the bottom of a split trash bag. Gravest Gravy features the band on the cusp of that fearsomeness, capturing the results of the Cramps’ 1977 Memphis recording…