Hentai Initiative ~Imouto to Itoko ni Nigirare Seikatsu~

The house where I live with my sister. A childhood friend’s cousin came from overseas. I decided to come back and stay at the boarding house. “Do you remember the promise that you would marry me?” When my cousin said that, for some reason my sister started to get nervous. One day, my sister and cousin came to my room He suddenly tied me up. “Aniki is bullied by younger people “You’re a pervert you love.” My sister’s meaningless words. I’m just being toyed with… What happens after this!?