Verb. To Masterbate with utmost stealthiness, similar to that of a ninja.
Spirited Away was such as shitty movie, I had to whip it out and ninjabate to pass the time.
ninjabate: define #2
To masturbate, fondle, or otherwise touch oneself sexually with one or more unaware person(s) in the vicinity.
“She was so hot in that movie, I just couldn’t help but sit back and ninjabate.”