Lingering-Scent Pill is a secret medicine that imperial concubines use. It emits a charming fragrance, but also keeps pests away.
Han Li made the pill upon Li Feiyu’s request. When Mo Caihuan pesters her father’s disciple for a gift, he tries gifting it to her, but she suspiciously/teasingly asks if he has given her a love potion/aphrodisiac.