Meaning of "Don't be a dog in a blanket"

As a child, my father (born and raised in the north-west of England) used to occasionally admonish one of us by saying "Don't be a dog in a blanket". I've never exactly understood the meaning of the phrase other than I remember it was usually used in the context of protecting some item in a selfish and sullen manner.

Has anyone else heard this phrase before and could they provide further context and meaning?

Solution 1:

The traditional saying/idiom is "a dog in a manger": it has been attributed to (and popularised by) Aesop's fables.

It is discussed in Wikipedia and theidioms.com

The short form of the fable as cited by Laura Gibbs is: "There was a dog lying in a manger who did not eat the grain, but who nevertheless prevented the horse from being able to eat anything either."

The story was first glossed in the 1st century CE lexicon of Diogenianus as "The dog in the manger, concerning those who neither themselves use nor allow others to use: Insofar as the dog neither itself eats the barleycorns, nor allows the horse to"

Your father had the saying wrong... :)