Raise a Loyal Dog [Sibling]

[The heroine Neptune. The male protagonist has been sent to Durban to study and graduate from high school] Zheng Yi only saw her brother again when he was eight years old. She doesn't need one more person in her life. Therefore, Zheng Yu must become her dog. Dog training requires patience. You need to suppress him when he is angry and comfort him when he is frustrated. The taste of candy and pain, and all his emotions, are given by you. Then—— "Zheng Yu, come here." She rang the bell. The man without a collar around his neck walked over quickly and lay on Zheng Yi's lap like a dog. Intention: sister-brother love and master-servant love