Imouto no Hou ga Onee-chan Yori Kawaii Desu yo, Senpai?

Even though you like my older sister, the person Senpai will be going out with is me! His confession to his classmate, Ayahi, the girl he yearns for was a massive failure and it's all her little sister, Azuki's fault, because she interferred! "I'm sorry, Senpai. As an apology, how about i let you do all the things you wanted to do with my older sister, with me instead?" Just like that, Azuki started teasing me more and more...

(Source: Fantasiabunko, translated)