Naisho no Wakana-san  

Secret Wakana, 비밀의 와카나씨, ナイショの若菜さん♥, ナイショの若菜さん

Wakana, a close friend and an older sister figure known as onee-san, attends a funeral with her longtime husband of 15 years. Later that night, she engages in a romantic encounter with the family's son, who is a young man studying for his college entrance exams.