FNS-229 | Misaki Sonoka, the younger sister, awakens to the pleasure of sexual release after being forced to use her breasts as a sex toy by her hikikomori brother who rides her on top and gives her a titjob.

"He used to be so kind..." Sonoka is the younger sister who supports her withdrawn, troubled older brother. But one day, after bringing him food, she is forcibly dragged into his room and forced to offer her G-cup breasts to her brother's desires. Ignoring her screams, he kneads her breasts and ejaculates all over them. Still, wanting to protect her brother's place in the world, she chooses to live as his personal breast sex toy. As they continue to have unprotected sex and titjobs, her brother begins to leave his room, craving her breasts. Though twisted, this is her hope for his rehabilitation. She stops resisting and devotedly accepts his sexual release. A sad and depraved story of codependency between siblings.