The biggest turn on for me was one evening when i was working in this office complex, after everbody had gone home.
I went into the ladies restroom / toilets which i knew was used from all the office girls upstairs.
i sat in one of the cubicles in the dark and the best waank ever...

Abcat Cine Club in London. Guys start by rubbing through their trousers and then can't help but openly masturbate themselves as the porn turns them on so much. I joined in on Thursday and loved it!

late night on a tube between stops! top of a double decker bus once, graveyards...er....woods... sure there's others.

In a church late at night.. after talkn to a woman Heather in the office

For me it has to be in the middle of a field next to a main road, about 3am, fully naked. Absolutely exhilarating!

Not unusual at all, but still one of the best jacks I ever had: in a hotel room in NYC. First time there, very jazzed about it. Level of excitement was high. Hardly got into the room before I threw my clothes off, lubed my quivering, rock hard cock up and went it. Stroked it long enough to work up a good load. Shot it clear past my shoulder - and I'm not much shooter.

Another one: back of a big old Chevy at a rest stop in Kansas. I was driving cross country in the summer. Wearing T-shirt and shorts. I had started during daylight playing and stroking my dick. It was dark by the time I got to the rest stop a few miles inside the Kansas border. I pulled up away from the other cars and got in the back seat. Plenty of light from the rest stop lighting. Pulled off the shorts and pulled the T-shirt up. Played with my nipples and worked my raging cock for about another hour before I finally let my load go all over my chest.

In a porn booth in Amsterdam. I was really high and unbelievably horny.
You could smoke in the booths as well!
I picked out a DVD (I made sure it was over 3 hours long), paid, then went in to a booth, put the DVD on, got naked and turned the volume right up so others browsing the shop were sure to hear
5 hours went past and I had cum multiple times.
Best. Wank. Ever.
I can't wait to go back!

adult theaters and bookstores, can always get some action when other guys see you jacking

Couple of years ago in a hotel room. Love when I get an opportunity for a short solo trip. No time limits, no worries about anyone disturbing you.
I got in around 7pm and by 8, I was panned out on the large double bed, naked with a massive horn. I edged for 4/5 hours, watched some great porn and chatted with a couple of guys over skype. In the end I was chatting to a bi guy. It really turned me on to cum for him and after so long building up, I shot an absolute mammoth load straight up into the air. My cock pulsed for 4 or 5 long squirts. I was so drained and happy at the end, and my skype partner got off on it so much he came a few moments after me.

Industrial estate in Morrabbin, Melbourne. I had been to a sex store and bought a masturbation aid which slips onto your cock. I put it on my cock while I was driving but I got so horny I had to pull over.

I pulled into a service road and turned into the industrial estate which was empty because it was early evening.

I started sliding this thing up and down my cock which was wonderful, but then a car drove in an parked across the car park. I didn't think they had noticed me so I carried on. Looking across I saw the couple in the car kissing and as I watched it became obvious they were getting heavily into it.

I decided to drive past them to get a better look, and they amazed me by waving for me to stop.

I had my lap covered by my hoody, and the sleeve still on my cock, so I pulled up and wound the window down. Then the bloke said straight out " you want to watch us ?" and opened the passenger door so I could see he was fingering the bird who had her skirt up around her waist and her bare feet on the dashboard.

I just nodded and pulled along side them, opening my door and pulling up my hoody to expose my very swollen cock stuck in this wank sleeve.

They just carried on, she wanked him, he fingered her, and I stroked up and down my cock slowly. It didn't take long before she bent over and started to suck his cock whilst he fingered her from behind.

When he came, he shot his load all over her chest and top, she moaned her orgasm and I removed the sleeve as my cock went into spasms and just unloaded without me touching it. It was fucking awesome. They just shut the door and drove off, leaving me with a lap full of cum and a red face.

I just got so turned on remembering, that I am going to wank myself stupid right now

In the woods on a hot day...numerous times- loads of sperm expelled from my balls on each occasion. In my cousins bed once when she rushed out the door as she was late...a real cumblast on my stomach. Last one was in my backyard when my neighbours daughter and her friends were sunbathing...i stroked just feet away...awesome times.