Getting a crush on a teacher may be a common predicament for sex-crazed adolescents, but not many of them have to share a home with the object of their obsession. Such is the quandary facing Katsuhiko (Taisuke Niihara), the protagonist of Toshiya Kominami’s “Young & Fine.”He’s a high school senior in a sleepy seaside town, who devotes most of his energies to playing rugby and trying to get past third base with his girlfriend, Reiko (Yuki Araho), when he should really be studying. After another evening of unconsummated canoodling at home, Katsuhiko learns that he’s getting kicked out of the annex he’s been using as his bedroom to make way for a lodger, Manabu (Yuka Kouri), who’s just started teaching at his school.This new arrival is gawky-hot and a hot mess. A former student of the school where she now works, Manabu is still haunted by memories of her unhappy teenage years, which she drowns out with swigs of whisky in the storeroom. Yup, she isn’t just a beauty with geeky glasses, she’s also a closet alcoholic — and, as she lets slip to Katsuhiko during a late-night drinking session, a virgin.