When someone gets their dander up they are angry or excited. Saying 'Don't get your dander up' means relax or calm yourself down.
I suspect it comes from dogs. Dark haired dogs will show their dander when upset (it can happen during a thunderstorm, or when upset at a strange dog, etc.). The appearance of white dander flakes on black fur is quite noticeable and led to the saying.
It means to become angry or agitated at someone or something. The phrase don't get your dander up means, "don't get your temper up." the definition for dander is temper. In other words don't get so angry... take a chill pill, as most people would say.
The slang meaning of â??dander upâ?? means to become angry. It can also refer to go crazy or freak out.
In "The Adventures of Tom Sawyer," dander is slang for anger. When Aunt Polly gets in a dander, it means she is getting angry or upset.
Dander is dead skin, much like dandruff. It is a fine powder and a major cause of pet allergies. Senstitive individuals get an immune reaction when they breathe pet dander. Using the word in idiom form refers to anger. If someone is "getting your dander up," it means they are arousing your anger. This usage is probably unrelated to the other meaning.
Get on your nerves, irritate you, get your dander up
To 'coin a phrase' means to have invented it or 'came up with it'.
Roll a joint
Yes. All pets have dander.
The Phrase "It is as handy as it is becoming" means it is as useful as it is up and coming.
The phrase button it up means to complete it or finish it.
Becoming more mature
This means that a person a has enough.