When Kid Cudi showed up on Letterman to do “Erase Me” with a guitar strapped on, we were pumped: He’d just told MTV he’d been playing the thing for all of two and a half months, so that he had the cajones to bust it out on national TV was mighty impressive. But Cudi’s guitar returned to late-night TV yesterday on Fallon — where he did his new song “Maniac,” alongside featured guests Cage(!) and St. Vincent(!!) — and, sadly, it looks like his handle on the instrument hasn’t markedly improved. Look, Vulture understands: Surely the whirlwind promotional cycle for his major-label release Man on the Moon II: The Legend of Mr. Rager has not left a lot of time for sitting at home with tab sites open trying to learn “Free Falling.” But the sooner he does learn to shred, the sooner the world gets that Cudi rock project we’re honestly looking forward to. Still, it’s a dope performance. More Cage on late-night talk shows, please!