Suddenly transferred to a distant location, I needed temporary housing and ended up staying with my aunt, Yumi, near my new workplace. Yumi worked as a nurse—typically serious, meticulous, and somewhat tense due to job stress, always composed and sharp-tempered. But one night, I accidentally caught her in her room, deeply engrossed in vibrator masturbation. Seeing her, usually so prim and proper, in such a lewd and passionate state completely shattered my restraint. I couldn't hold back any longer.