This is not done because the positive fuel has become stale (as is the case when devaluation occurs in the context of an intimate partner primary source) but is an adjunct of wanting to achieve some other aim.
The two most popular aims are control and triangulation. We will provoke a negative fuel response from children in order to exert control over them, for instance, taking a toy away or forbidding them to do something that they enjoy such as watching a certain television program or being allowed some sweets. This reinforces our control.
A child is no different from any other appliance and must be subjected to our control. This control is not exerted for the benefit of the child, for instance, stopping the child from eating sweets every day because it is unhealthy, but is only done so we can establish control. In terms of triangulation, the negative emotional response will be achieved for the purposes of triangulating you.
For instance, we may suggest to the child that mummy does not love the child so it becomes upset. We only care about the reaction, not the well-being of the child. We may say that the child cannot do something on your instruction, in order to both upset the child and thus gain negative fuel and at the same time smear you through this triangulation. Thus, when negative fuel is sought from a child it arises in conjunction with the desire to control and/or to triangulate. Understanding this attitude will help you save children from narcissist.
3. Traits and achievements
The traits and achievements of the child are up for grabs in the same way that we steal and acquire traits from adults in order to furnish our construct and make ourselves look even more appealing. Our sense of entitlement is such that the child has only won the race, come top of the class, swum that distance, secured a place on a vacation scheme as a consequence of our brilliance. We will remind you, the child and third parties that this is the case. Repeatedly.
4. Smear and brief
We will smear and brief against you at every available opportunity. Irrespective of the reasons why the relationship between you and us ended, we will not rise above the desire for smearing for the sake of the children. If there is an opportunity to take a pot shot at you, it will be taken. The needs of the children do not ever come before our needs. Thus if they are upset by what we say about you, we receive fuel and do not care how it affects them. If they begin to dislike you because we suggest you are too strict, we will not counter that but rather we will cultivate this position to our advantage.
Just like you, children can cause criticism to us. Rather than soak it up as a mature, well-adjusted parent would, we will lash out when there is a perceived or actual criticism of us delivered by the words and/or actions of the child. This will as ever result in the ignition of fury and the manifestation of heated fury or cold fury. We will sulk with a child, turn away from them if they want to support and/or shout at them. The fact they are a child is meaningless to us. The fact we as a parent owe obligations to them to behave in a mature and responsible fashion to them does not matter because our needs come first.
6. No sense of responsibility
We have no sense of responsibility or obligation to children. A lesser narcissist will see no need to maintain maintenance payments and will be content not to see work. A greater may well make such payments, not because he cares about the children but it is done to show to everybody else how generous he is and also to make you look bad if your financial contributions are not as substantial.