To surprise a ninja and get smacked by his spring-loaded erect penis as a result (or wang). In everyday usage, a term used to describe the result of colliding with a ninja or someone of ninja-esque qualities, resulting in disorientation and humiliation.

The ability to ninja-wang or to cause ninja-wangification or to possess a ninja-wang is reported to be an ancillary reason for a ninja's inherent stealth.

"Ninjas don't just walk slow to not be heard ..." -- John S.

Someone people turn to when they're sad who makes them feel better.