At my part-time job, my senior coworker Hikari was a rough-around-the-edges, tomboyish girl with an unmistakably big chest that stood out even under her work clothes. Every time I stole a glance at her, the sight of her cleavage when she bent over or the shape of her bra showing through her sweat-drenched T-shirt sent shivers through me. One day after work, while I was getting ready to leave in the office, Hikari suddenly teased, "Hey, let me see your cock," reaching down and touching my crotch. In that instant, I lost control and came right then and there. Drenched in sweat, I ended up losing my virginity to her on the spot. From that moment on, our relationship gradually deepened, evolving into a sexual one where we satisfied each other's desires as fuck buddies. Her bold, assertive nature intertwined with unexpected tenderness, drawing us closer and intensifying our bond.