Osananajimi no Saishou Hosakan kara Osowaru "Love Ecchi"!? Shojo na no ni Neya Kyouikugakari wo Haimei Shitara, Dekiai ga Hajimarimashita

Christina, a marquise living in seclusion after the death of her husband, is ordered to teach the crown prince “nighttime experiences”. However, although she is a widow, she has no experience with men! In a panic, she asks for help from her childhood friend Ruffino, an aide to the Prime Minister, who has come as an emissary....?