The rest room appears to be the best place.
In the parking lot can be more dangerous. How do you know when someone is approaching when you are in the final stages and totally focused on the task in hand?
at home... at work... in the car... pretty much anywhere... usually cum 4-5x / day on average... so I stroke every opportunity I can.
Well has anyone jacked off while driving down the interstate on a long trip or gotten a blow job? Not exactly at work but.