what is one word or phrase to describe junior and a quote that shows that junior is that word and why does that describe junior

Junior is a funny guy. He has a lot of other things going for him but his humour is witty and infectious. Check out the opening lines of the story and you will see Junior's personality and intelligence shine through his witty narrative:

Okay, so that's not exactly true. I was actually born with too much cerebral spinal fluid inside my skull. But cerebral spinal fluid is just the doctors' fancy way of saying brain grease. And brain grease works inside the lobes like car grease works inside an engine. It keeps things running smooth and fast. But weird me, I was born with too much grease inside my skull, and it got all thick and muddy and disgusting, and it only mucked up the works. My thinking and breathing and living engine slowed down and flooded.

My brain was drowning in grease. Ch. 1