Deez Nuts spelled backwards. Essentially a way to tell others to suck on or get off your nuts ina manner in which they would be oblivious to. (which is what makes it funny)
"Dude tell your mom not to handle the stunzeed. She could get seriously injured that way."
An adult, most commonly a male, who has never fully developed or matured emotionally and is characterized by a low degree of self awareness, awkward interactions with other people, a lack of empathy and an inability to achieve intimacy.
Gary: "Ken, I hate to be the one to tell you this but Uncle Gilbert has cancer."