HMN-259 Kokoro Ayase is loved so much by her sister that she secretly makes a baby.

"Ah! My sister's boyfriend was looking at my boobs!" My first girlfriend's sister has super big boobs! - ! - Even though I have a girlfriend, she secretly shows off her estimated G-cup breasts and seduces me! - "I'm going to tell you that I creampied you~?" Even though she was supposed to be important to me...I gave in to temptation and begged for more, and my reason collapsed! - ! - My sister, who is bright and charming and has big boobs, completely controls the pace, and I secretly cum inside her and have sex with her!