A technique designed for tight spaces and no privacy.
In the Spring of 2010 my Army unit was at a training location in the California desert. There were about 100 cots lined up in an enormous permanent tent-like structure. Now I usually like to masturbate about 4 times a week. And after the end of week three without a moment alone, I knew I had to do something. The tingling ache in my balls, made me feel desperate for release. That night lying in my sleeping bag I inched my shorts down a few inches to where just about the last third of my cock was out of the waistband. I grasped it behind the head, like always and tried to pull. Instantly I knew there would be too much noise and movement.
So out of frustration I began to squeeze with my hand just increasing and decreasing pressure rapidly....having been three weeks since I had seen my girlfriend of the time, it didn't take long before I felt those familiar contractions begin under my balls as they squeezed up tight to my body and contraction after contraction shot through the length of my cock. my hand, belly and unfortunately my sleeping bag were soaked with warm cum. As it happens it rapidly cooled until there was an uncomfortable cold wetness around me, but I quickly went to sleep. Next time I'd just stick a sock over the head to catch the inevitable mess.