Rap can be as nasty as it wants to be, and, thanks to the 2 Live Crew obscenity trial, everybody knows it. Yet explicit rap tunes everything from the exaggerated sexual boasts of the Crew to the ''gangsta'' playacting of N.W.A. pose a new and complex set of questions. Are sexual rap songs merely dumb-fun party records Redd Foxx set to a drum track or should they be treated as appalling antiwomen tracts? Are rappers who talk like thugs trying to dramatize conditions in the black community or merely toughening their image? Do they actually encourage violence? None of these new records fully answers those questions, but in its own way each addresses the contradictions inherent in explicit rap.
''The Product'' appears on Explicit Rap, an anticensorship benefit album that's like a K-Tel compilation for the nasty-minded. The record has more than its share of graphically offensive rhymes, from the 2 Live Crew's ''Me So Horny'' to Bobby Jimmy's castration fantasy, ''Wienie Whistlers,'' and N.W.A.'s hateful ''A Bitch Iz a Bitch.'' But hearing one saucy rap after another doesn't encourage rage, just laughter. And in fact tracks like Choice's ''Payback,'' a proud assault on macho male rappers, actually are wholehearted chuckle-fests. B+