Pink no Curtain  

ピンクのカーテン, Pink Curtain, Curtain of the Pink

The manga "virgin boy okuyama" by george akiyama follows the story of a young man named okuyama who works at a supermarket and has no success in romantic relationships. his life changes when his sister noriko moves into his home, causing him to develop strong feelings for her. however, she sees him only as a brother.