My grades haven't been good lately. Seeing that I was studying hard, my sister encouraged me by promising to comply with any of my requests if I got a perfect score on the next test. Motivated, I didn't leave my desk, studying hard until the day of the test. And as a result, I got an absolute score on not just one but the entire test this time. And as promised, my sister will listen to my request. During the three days my parents were away from home, I immediately gave her a "lewd bunny" suit to wear, although she didn't want to, but because she had promised, she had to accept. Not only that, I asked her to call me my master, cum my cock, suck my cock, let me fuck my breasts, and even fuck my sister! At first, it was because she fulfilled her promise, but the feeling of embarrassment when wearing revealing clothes, the feeling of stimulation when calling her brother her master or even fucking her brother, the feelings that seemed to awaken the lust inside her. She took the initiative to want to be fucked by me, she wanted to be my "lewd rabbit". Three days passed, and my parents finally came back home, and we returned to normal. But my sister still promised that if I got a perfect score, she would obey any request of mine.