Tits (2013)

Despite assurances that his condition is common and will pass, thirteen year old Sam is horrified to find he has grown a pair of breasts. His terror intensifies when the resident school bully (the only person to have discovered his secret) sets in motion a tense game of cat and mouse, as he subtly threatens to expose Sam to the school, building inexorably towards a confrontation that neither of them could ever have imagined...