Shin'yū no otōto ni kyūai sa rete imasu 〜 kon'na haraguro wanko nante shiranai! 〜.

How could that cute little guy do something like that at night!? Ren Fujikawa, the younger brother of her best friend, has been obsessed with Aoi Takano since they were children. When they meet again after several years, the small boy has now become a handsome university student! "I'm sorry, Aoi-nee-san...I thought I could hold back..." That night, my younger brother approaches Aoi...?! "I can't believe I'm being pranked by a college student who's five years younger than me?!" Since then, Aoi has been overwhelmed by Ren-kun's aggressive attacks and has easily fallen. I didn't even know that it was all according to his plan...