Not stupid at all. Wet and dry refers to fuel when you're talking about nitrous. A dry shot is a shot of nitrous with no fuel. Conventional nitrous systems use a fuel and nitrous solenoid. The system adds additional fuel at the same time as nitrous. The dry shot adds no fuel. With a dry shot, there's more chance to hurt the motor by leaning out. A lot of people try to lean out the nitrous to get it as fast as possible, but that's risky. If you use it safely, you won't have a problem. Stock cast pistons can take about 100 shot without problem as long as the ring end gaps are filed right.
