Don't Show That Melting Face to Anyone But Me: My Puppy-Like Childhood Friend's Little Brother Was a Younger Sadistic TopNewそのトロけた顔、俺以外に見せるなよ？～わんこな幼なじみの弟は年下鬼畜攻めでした～; Sono Toroketa Kao, Ore Igai ni Miseru na yo? ~Wanko na Osananajimi no Otouto wa Toshishita Kichiku-zeme deshita~

Miku is a BL author whose editor has just torn into her work, telling her it has no soul when it comes to the erotic. Stuck and unable to write her way out of the slump, she confides in her best friend Ai, who suggests a solution: why not ask her little brother for help? Kei is the younger brother of her childhood friend, a boy she grew up alongside and has always thought of as a cute kid brother. But that understanding is completely wrong. "Miku-chan, wouldn't I make good reference material?" Behind that puppy-dog smile hides his true nature: a younger, sadistic top who has been single-mindedly targeting Miku all along.