Wallflowers, beware: We're approaching a point in which leaning back will no longer be a suitable response to a banger. A dance-music revolution is taking hold of R&B (electro abounds!) and even hip-hop (snap music ain't snap music without the snapping). No surprise the dance-rap fusion is being realized undergound: At least half of the latest tracks from Boston-based duo 7L and Esoteric rushes by via accelerated tempos and clacking Bambaataa breaks. Even when 7L's beats aren't frenzied, they're still mechanical. "Reggie Lewis Is Watching" is Rubinesque, with M.I.A.'s stomp. Esoteric may not be the greatest rapper (he most often sounds like fallen radio personality Star hijacking a Jay-Z flow), but he takes nothing away from the beats. At the risk of sounding soft, he plunges right into the dance-oriented numbers, never sounding less than secure. (He points out he doesn't say "no homo" after a possible double entendre, because "I don't have to.") He's more man than rapper, a true rarity in hip-hop.