"Day & Day" by Jeong Sewoon is a sweet and heartfelt love song that expresses the narrator's feelings and desires for their loved one. The lyrics depicts the emotions and thoughts of the narrator as they navigate their day-to-day life with their significant other. The song starts by wishing the loved one a good morning or evening, wondering what words are best to express their feelings. The narrator describes how being with their loved one feels new and exciting, and they can't help but marvel at the fact that everything seems to be directed towards them. The chorus emphasizes the bond between the narrator and their loved one, comparing their relationship to the sun and the moon. The narrator asks their loved one to stay with them throughout the night, and when the sun tilts towards them, they promise to open their heart. It conveys the desire to cherish and hold their loved one tight. The second verse describes the narrator's feelings as they become slightly overwhelmed with love. They feel a burst of emotions and shower their loved one with affection. Whether it's day or night, their time stops when they are together. The chorus repeats, expressing the narrator's plea for their loved one to stay by their side and open their heart when the sun tilts towards them. They convey the desire to embrace each other tightly during those moments. Overall, "Day & Day" portrays the narrator's deep affection and longing for their loved one. It accentuates the joy and happiness they feel when spending time together, and their desire for the relationship to continue deepening and flourishing over time.