The best time I ever masturbated was when I was driving home one time late at night and I got really horny. I could feel my cock pulsing in my pants so I decided I just had to do something about it. I was wearing tracksuit pants so they came down easily and revealed my huge cock. I started to jack off there and then and it was such a turn on with people around you the whole time and not knowing what you're doing so near by. When I came I came so good I the car started to sway on the road.
It made a really big mess so from then on I started to use a sock when I did it so there was no clean up afterwards.
This led me to another technique of using a warm wet sock. Get a nice, heavy sock and run it under warm water and then use that to masturbate. The warm fabric against your cock feels so good you'll come strong and hard.