Shounen no Hatsukoi wa Bishoujo ♂ deshita

Tougo Ushiwaka reunites with his childhood friend and first love Ren Ryuugasaki after about 10 years. However, Ushiwaka had been traumatized to discover that Ryuugasaki, who he had thought was a girl, is actually a guy with a fondness for cross-dressing.