"Senior...where are you looking?" The unsuspecting, big-butt, tight-skirted OL (office lady) was immediately penetrated from behind! (Yoshizawa Ria FNS-068)

I've become the person teaching Ria, a somewhat naive new office lady with a large butt. My heart races as I take care of this adorable new junior. One day, while Ria and I were working overtime alone, I saw her plump butt peeking out from under her tight skirt and became fully erect. Even though I knew it was wrong, I immediately had sex with her from behind. "Oh no!" I regretted it, but I was still grateful to Ria for acting like nothing happened the next day. But I just can't resist seeing that big butt...