If you can be a little quiet, find a place that had bathroom stalls with dividers that go to the floor (some nicer restaurants, some golf clubs). Or, find somewhere that has single-person restrooms that lock (some fast food places and office buildings).

Or, meet up in parking garage and do it in the car. Just park where there are fewer cars, and take a look around for cameras.

Also, some stairwells in buildings that have elevators can offer a semi-private location as long as you're ready to put it away if you hear a door open.

I've only been doing it for just under 4 years now. We had the same problem of where to go at first but we've settled on eachothers house. We tried in the car but didn't enjoy it.
My buddy and I are both married so opportunities don't occur that often. We tend to keep eachother aware of our respective wife's movements as and when we know.
If for example I know for sure mine will be out for a couple of hours I let my buddy know, and if it okay for him, he comes round here. He does the same when his wife is going out.
We play it ultra safe. If it's just a couple of hours, we just drop our trousers and have fun together like that. If on the other hand, we know it's for half a day, then we'll get totally naked together and have even more fun.
It means we don't get together as often as we might like, but it works for us.

If not at home or in my car I did it in a port-a-potty while working at a beach on a holiday weekend and looking out the screened window looking at some hot woman.

Did this at a rave, was hot jerking off in there with loads of people around.

Get a room overlooking the pool.

There are some private places on the beach, like on Gandy Blvd. overlooking south Tampa Bay, where guys hook up with other guys, but it is risky. Every few years, some righteous do-gooder gets up in arms and alerts the police, who, on the orders of the Pinellas County Commission, dutifully raid the mangroves where adults discreetly get nude and play.

No, it's not the most scenic place to have sex, but when you're horny, you're not really looking for atmosphere, are you? Sometimes, you just want to get sucked off and go, and this beach reportedly is good for that. (I don't know about that for certain ... just what I've seen and heard.)

Its a bit weird but cemeteries are quite good I would think. I have actually fucked 2 women in cemeteries, one in broad daylight. They are often pretty deserted and you can see people coming from some distance usually.

Well, I don't have experience with a buddy, but me and the wife love getting naked outdoors. I'd definitely suggest it as an option. We've explored a variety of places, from hiking in state parks, exploring wooded lots, riverbanks on a canoe trip, etc. Key is to find a private area off trail or secluded enough to avoid accidental discovery. Avoid those places that are known sex hangouts. To begin with, lot of weird people frequent those places, and, if they are known to be sex spots, then law enforcement will have a presence.

Find a quiet patch of woods and have fun. Nothing hotter than having fun in the outdoors.

If you can find an X rated bookstore that has viewing booths in the back, I think it's a great place to play. Most allow more than one person to a booth, some have glory holes if they don't allow 2 to a booth. I have always found them to be safe, in that you are not going to get busted in there. I've never seen any law enforcement around any of them. That's why people go there, and the places usually make a lot of money from people feeding the machines all day (which they may use to pay off cops ?). The risk of course is not playing safe with a sketchy stranger. But if you do what I do, plan to go with a buddy you know or at least have "vetted" somewhat, it can be an ideal place. The only problem could be finding one in your area. I'm lucky in that there several of them fairly close by. If you've never tried one before, I suggest you try it.

Adult porn theatres and adult video booths/glory holes are the best places to jerk off with a buddy. I've also done it in rest areas, parks, and in the woods - although these are much riskier. I've also been to bathhouses - jerk off in the showers or play rooms where other guys can watch you.

I've sucked off many guys in all these places! Most of them shot their cum loads in my mouth - which I've always swallowed!!

Know a few trials in my area great for hikes and getting naked in the trails and not busy. Like the warm sun on my body and hikes on these trails and sometimes will meet someone that is also naked on the trail. Nice to meet them and maybe get off together when we notice both of us are boned.

In my office right this second

Wife jerking me off in the car is always a winner!

Beach
Park restroom
Nature trail
Gym locker room
Steam room
Car
Adult book store

I have a buddy that I go "hiking" with frequently. Once you get a bit off the beaten trail, there is plenty of privacy. We always make sure to bring a blanket to put down so we can jack, suck, and fuck. I really enjoy playing outdoors and it is plenty secluded out in the woods. Plus, it gives that nice dirty "cruisy" feeling