Tetsuya Taguchi is a civil servant who develops persistent priapism after accidentally dropping a book on his erect penis during morning arousal. This condition forces him to constantly wear a heavy coat for concealment, leading to profuse sweating and a hunched posture in public. His symptoms originate from post-traumatic stress triggered by his divorce three years prior, specifically his ex-wife's new relationship and her subsequent adoption of revealing clothing. Taguchi struggles to express emotions or set boundaries, making him vulnerable to exploitation by colleagues who take advantage of his inability to decline requests.

During treatment at Irabu General Hospital, Dr. Ichirō Irabu employs unconventional methods, including urging Taguchi to confront his ex-wife directly. This confrontation results in her apology and announcement of her pregnancy, which facilitates Taguchi's emotional closure regarding their past relationship. Following this resolution, he demonstrates increased assertiveness by establishing personal boundaries and refusing unreasonable demands.

Across adaptations, Taguchi's psychological state receives visual representation through recurring motifs. His uncontrollable arousal manifests as intrusive "Male Gaze" perspectives in the anime. Additionally, during therapeutic injections administered by nurse Mayumi, he exhibits an animal motif transformation into a rhinoceros—symbolizing his "horniness"—consistent with the series' thematic use of expressive metaphors for patient conditions.

In the live-action film *In the Pool*, Taguchi's storyline follows similar narrative contours as the original literary version, depicting his condition and therapeutic journey. His occupation remains consistent as a salaryman across all media iterations.