Narim, who has developed feelings for his stepbrother, Sewoon, after his parents' remarriage, accidentally discovers Sewoon's ideal type. Shocked to learn that his ideal type is someone who is "good at that", Narim, who has no relationship or dating experience, decides to purchase sex toys in a desperate attempt to become his ideal type, despite knowing it's an unattainable love. One day, when Taehyun visits Narim's home, he discovers the sex toys and confronts him. When Narim confesses that he bought a dildo to become his stepbrother's ideal type, Taehyun is dumbfounded. "You think you can practice with something so small? How can that possibly work?" he scoffs. "Then what should I do?" "Why don't you just do it with me? Let's practice sex together," Taehyun suggests. Taehyun offers to be Narim's practice partner... But is sex really something that needs to be practiced?