The Ninjina (Ninja + Vagina) is the mascot for the "Pussy Air Freshener," a cherry scented adult novelty product that you can display in your car, garage, or dorm room.
Phil: "Dude, it's pretty rank in here."
Jack: "Yeah, I wish the Ninjina would pay us a visit."
Phil: "The Ninjina?"
Jack: "Yeah, the Ninjina. He suddenly appears in a puff of smoke, and throws Pussy Air Fresheners like Chinese stars."
Phil: "He what?"
Jack: "You heard me."
v. To be or act like a ninja; to perform any ninja relatedactions (steal, sneak, kill, fight, attack); to perform with stealth or skill; to use any form of martial arts.
They must ninjiate into house, or there will surely be consequences.