Aki Ayamatsu appears in the second segment of the Sensitive Pornograph OVA. Initially introduced as a pet rabbit named "Aki-chan," he is cared for by pet-sitter Kōji Ueno. Ueno discovers Aki confined and unclothed in a client's closet, revealing his role as a captive and sexual subordinate to an unidentified man.

Aki has gray or silver hair reaching his neck and red eyes. He is occasionally depicted wearing bandages and a turtleneck garment. His background establishes him living under the control of the mystery man, who treats him as a possession or "pet."

During Ueno’s visit, Aki and Ueno engage in a sexual encounter, secretly recorded by the unidentified man. This incident sparks a pivotal change: Aki rejects his former role, informing the mystery man he refuses to remain his "pet." This declaration signifies his decision to pursue autonomy and end the subservient relationship.