The remaining jizm or spunk that eminates, some time later, from ones japs eye after a wank. Even after a good shake and pipe clean.
After a morning wank before work, you clean up and head to work only to find when you go for a piss you have found a whole load of Ninja Jizz.
by tehsnrub August 29, 2009
When there is visible jizz on one's pants, yet the wearer of said pants has no idea how it came (no pun intended) to be there.
Emily: Nice white splotchy thing on your crotch...
Cara: Oh, it's just the light.
Emily: Are you sure...?
Cara: Unless I'm being ninja jizzed, there is nothing there!
Cara: Oh, it's just the light.
Emily: Are you sure...?
Cara: Unless I'm being ninja jizzed, there is nothing there!
by ThatPurpleChik March 22, 2010