Rumors spread that senior colleague Mikako Horii was dating the department chief—cheerful, stunningly slender, and wildly popular among coworkers. After a late work night, she invited me out for drinks, and we impulsively slept together, discovering incredible chemistry that turned us into secret lovers. Her big ass became the talk of the office, and in her bold Kansai dialect, she teased, "Look... my favorite big ass is all yours, go ahead and do whatever you want." Unable to resist her curvy temptation even during work hours, I secretly jerked off while she provocatively thrust her hips, discreetly fucking her over desks. Getting caught would be disastrous, but the pleasure was so intense I couldn't stop myself.