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). And it's no surprise the dance-rap fusion is being realized underground: 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 Rubin-esque, with M.I.A.'s stomp. And while Esoteric may not be the greatest rapper (he most often sounds like fallen radio personality Star hijacking a Jay-Z flow), 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.