This happened last summer.
On the 11th hole at my golf club, there is a set of trees that blocks off a portable washroom. I was out for a round of golf by myself after work. I was working with a new girl who was obviously new to golf course maintenance.
She was my age, wearing a short skirt, tight strap-less shirt which, so proudly, showed off her 36C boobs and a pink bra which you could see from behind. With that, she was also wearing a matching set of panties that were unbearably too small to fit comfortably unless you really wanted to get to yourself fast. She continually bent over to pick up loose golf balls and would leave herself completely exposed.
I never made a move on her despite my better judgement, *wink wink*. I thought it better see how the next couple of days working with her would be.
So, as I was playing my round, I was really thinking over if I had made the right decision to wait or not, when I noticed I was getting very, very, VERY horny. I was nearing the 11th and thought that it would be the best place to take a break and go jerk off in the washroom. It was a really cloudy day and people were expecting it to rain so it was basically empty on the course.
As I finished the 11th hole, I put my bag under the little over hang they made to keep golfers dry if a sudden storm meant they needed shelter. I went inside, undid my pants and slid them down, quickly followed by my briefs. My erection sprung forth like a caged lion. I sat down and became engrossed in imagining my new co-worker doing a little strip tease in front of me. (because of the position of the washroom almost no one used it because of the preferred pro shop one, so there was virtually no smell.) I quickly realised however that I was going to need a bit more today. I went out of the small room, still with my cock in my hand and my pants down, grabbed my putter, and went back inside.
In no way am I bi, but after many suggestions to try masturbating with something up my ass, I am hooked. I used the longer end of the putter, and washed it off with water and soap from the water fountain and soap dispenser outside. I spit on my hands and combined with my pre-cum, lubed the putter. I sat up a little and slid it right between my butt cheeks, then gently slid the cold metal into my hole, like always, it was electric.
I began to stroke myself again, much better. I started off slow, keeping in time with my humping of the putter, but soon got carried away with the humping and not so much the stroking. I loved the feeling of the cold metal in contact with my warm insides. I knew that I was gunna cum even while doing the short staggered strokes of my hand over my dick. I once again imagined my new co-worker stripping down and stroking my cock, moving a dildo from my ass to hers.
Almost instantaneous as I was imagining us cumming together, I let off about 4-5 strips of hot white cum that splatterd on the door. I really didn't feel like stopping, so I reapplied the lube to my putter and went a second time. It didn't take much time till I let off another 2-3 splurts on the door. I cleaned myself off using the paper towels in the washroom but left my mess on the door.
I walked off without any one noticing I was there and finished up my game. A couple of days later I made my move on the girl, but that's another story.