In my mid-twenties, I worked in a furniture store along side two women. I had an out-of-control penis (it has ruled my life) which meant that I spent many hours a day masturbating. I remember one day I was sitting at the sales desk in a Danish 'kneeling chair' which rocks to and fro, and, before long I had a ridiculously prominent bulge, which my rocking turned into masturbation as my cock strained against the tight slacks I was wearing.
There was little traffic in the store that day, so much of the day centered around the two women sitting next to me studiously ignoring my pulsing bulge. At the end of the day, the women went out the door while I stayed to lock up. I turned out the lights, and in a frenzy of horniness, I stepped behind a wall panel that covered a portion of the mirrored wall at the rear of the showroom, and threw off my clothes. I started stroking furiously, and rose up on my toes and arched my body, while thrusting into my fist and making frantic little steps along the mirrored wall. I knew I wouldn't be seen from the road in the dark showroom, but there was plenty of light for me to watch myself as I rapidly climbed to orgasm.
After about five minutes I dropped to my knees, and bent back till my head was on the floor, and then fucked straight up into my hand for another minute until, I fucked up into my fist one last time and strained to thrust my cock straight to the sky, supported just by the tops of my toes as my body arched like a bow and I shot rope after rope of come six feet into the air and it fell back onto me and the indoor-outdoor carpet. I collapsed, and heard the sound of the door cylinder clicking! I scrambled to my feet and scurried behind a desk. I peeked over the desk and saw the car of one of my fellow employees backing away from the curb.
I put my clothes on and hurried home, sure I would be fired the next day. The next day she pulled me aside and said that she had seen me from just inside the front window. She said that, though she thought I had put on a spectacular show, and actually asked the measurements of my erection (7' long, measured on top, and 6' around), she knew I was masturbating frequently during the day (I would jerk off at the bathroom sink and forget to clean my come off of the mirror) and after work, and it would have to stop, as there was a risk someone from the public would see me, and not be so impressed. I agreed, and from then on I went to my car to masturbate during the day, and I did it right after work on the drive home.