I have been a public masturbater for years.
Public washrooms are generally a good place to start - They provide some privacy and let you get comfortable with yanking your chain when other people are around.
Some of my favorite spots:
* Food Courts: A full on rush. Wear some loose fitting shorts, have a meal in front of you, and slip your hand under the table and work it. There is a lot of nice eye candy to enjoy the moment to. You can always blow your load on the floor under the table.
* Highway Overpass: Another rush. By the time anyone figures out what you are doing, they are long gone past you (take your chances during rush hour). Releasing your load is clean and simple. Bring a paper towel for post load clean-up (tissues suck! Too sticky)
* Parks: There are numerous areas in a park to pleasure yourself - Beside a tree, on a picnic table, standing behind a park bench...Again, a load can be ejaculated on the ground and forgotten.
* Parking Lots: A surprisingly fun place to yank the chain. A load can be deposited any where hassle free.
* Subway: Not much to say as this has been done by thoudands.
Some daring one-off situations:
* Grocery Store: I wedged a loaf of bread in between the rails of a grocery cart. Once hard I entered the bread. I would pretend to be looking at the products on the shelf and move the cart forward and backwards while my cock was buried in the loaf of bread. I shot my load into the loaf of bread and waited for my cock to shrink back to a flaccid state. The bread soaked up my man juice. Fresh white bread works best.
* Skydome: During the heyday of the BlueJays I was able to stroke myself to completion in the stands during a game. I rigged a box of popcorn with a fake bottom and had it filled with an oven mitt. I glued popcorn on the top for presentation purposes. Wearing track pants, I placed the box in my lap and slipped my hard cock up into the popcorn box and worked myself to a homerun.
Tips`
* Paper towels or small cloth rags are best for clean-up
* Adult diapers can work in some situations, but they are bulky
* Always smile when jerking off in public
* Control your grunts and moans of pleasure
* Be prepared to run - Some people are offended by public masturbation
* Always wear loose fitting shorts, track pants or a dress or skirt