Spare and sultry, with muted beats that throb like a pulse and judiciously deployed saxophone breaks, the debut EP from Philly duo Marian Hill is designed for hot nights. “Boy, if you wanna go, I would not mind,” coos singer Samantha Gongol on “One Time,” her languorous purr playing footsie with finger-snap percussion and that come-hither alto sax. Sway draws on minimal R&B, the downtempo trip-hop of premillennial acts like Morcheeba, and classic torch songs, providing a note-perfect soundtrack for the sleekest, steamiest boudoir.