An ass that you cannot see. According to the person with this ass, it's apparently there, but not visible to the naked eye. This is just an excuse for a woman with a really flat ass.
Finneh: I caught some bitch looking at my ass a few days ago.
STEFFFF: maybe it was my ass
Finneh: What ass? OBRN!
STEFFFF: its there. =(
Finneh: So apparently you have a ninja ass.
STEFFFF: maybe it was my ass
Finneh: What ass? OBRN!
STEFFFF: its there. =(
Finneh: So apparently you have a ninja ass.
by Finneh December 18, 2007
Near the end of intercourse, the man pulls his penis out of the vagina and slips it into the girls ass and unloads semen into her rectum before she realizes what just happened.
by va jay jay king April 4, 2010
One who engages in anal sex so quickly and stealthily that the other person is unaware that it has occured.
by FAH Q 2 January 18, 2006
by Prycey September 9, 2003
A mythical being who exists to give people wedgies. As with the Tooth Fairy, Santa Claus and the Easter Bunny, the Ass Ninja visits all the little boys and girls in order to bunch their underwear at the worst possible times.
"Dude I totally just got visited by the Ass Ninja! Cover me while I pick my underwear out of my butt."
by Dark_Angel August 25, 2012
An elite group of ninjas that discretely enters homes and rapes the shit out of whatever is living in them.
Also, Ass Ninjas are a threat used by parents, telling their children that if they don't go to sleep Ass Ninjas will get them.
Also, Ass Ninjas are a threat used by parents, telling their children that if they don't go to sleep Ass Ninjas will get them.
Last night Ass Ninjas broke into my house and raped me!
Go to bed now or the Ass Ninjas will get you!
Go to bed now or the Ass Ninjas will get you!
by TeddiGramz December 29, 2010
A ninja warrior who, quite literally, kicks ass. They aim straight for the buttocks and pummel mercilessly. See also: 'munkfuck
by Snnnnickerdoodle January 25, 2007