A wispy mix of boy-boy romance and noir-lite potboiler, the Shumanski brothers’ (Wrecked) latest wastes a promising premise by loading up on tender whimsy and skimping on grit. If you’ve ever wondered how Gregg Araki’s cinematic sensibilities might fuse with mumblecore mopery, Blackmail Boys is your answer. The film focuses on Sam (Nathan Adloff), a young art student struggling to make ends meet in Chicago who begins turning tricks. When his long-time boyfriend, Aaron (Taylor Reed), joins him from Nashville, they plot a score at the expense of a closeted, Bible-thumping celebrity john (Hannah Takes the Stairs director Joe Swanberg) with a mean streak. Their plan hits a snag that could have been avoided by watching a John Dahl movie. Blackmail Boys is enlivened by the Shumanskis’ jarring, customarily graphic sex scenes and understated humor (Aaron ponders whether “cocksucking Christian” is hyphenated as he scribbles a blackmail note), but lazily resists a resolution in which anyone but the obvious heavy pays a real price. That character’s hypocrisy is punished, but its wider implications evaporate along with the film’s central partners-in-crime setup.