The kill zone on a deer or other game animal, but primarily referring to the heart (since it is a pump.)
"Would you look at that majestic protein packed beast!" exclaimed an excited Ted Nugent in a barely controlled whisper. "I am about to slide a broad point right through his pump station! Watch closely boys and girls!" Whoooooosh!!!!
One who is well skilled in the art of the Pump Shotgun in games such as Counter Strike, and jump around while killing people in the air...much like a ninja. Thus the term, Pump Shotty Ninja.
"Dude, that guy is such a Pump Shotty Ninja. He just wtfpwned me."