The act of greeting someone by gently squeezing (and hence exciting, and possibly putting a smile on) their nipple. Usually followed by a wink. Not recommended for greeting someone of the opposite gender, but results do vary.
Every time I see Billy, he nippleshakes me but I never get the time to do it back because I would lose all my senses for a couple of seconds.
James tried to nippleshake that girl he had a crush on. He thought it would have a similar effect to when I do it to him. He was wrong. Now he has a bruise on his right cheek to tell the story.
1. Hungry. Usually slightly hungry or simply wishing to give the impression of being slightly hungry. Derived from nip as in a small bite.
2. A little cold. The feeling of being cold but usually just a small amount mostly from a breeze and a lack of a jacket or coat. Thus not usually used to describe wearing multiple layers and still being a little cold. Derived from nippy.
1. I'm a little nippish, do you want to get some lunch? If not I'll be fine until dinner.