Appeal to flattery is a fallacy

Fallacy

In logic and rhetoric, a fallacy is usually an incorrect argumentation in reasoning resulting in a misconception or presumption. By accident or design, fallacies may exploit emotional triggers in the listener or interlocutor , or take advantage of social relationships between people...

 in which a person uses flattery

Flattery

Flattery is the act of giving excessive compliments, generally for the purpose of ingratiating oneself with the subject....

, excessive compliments, in an attempt to win support for their side.

Flattery is often used to hide the true intent of an idea or proposal. Praise

Praise

Praise is the act of making positive statements about a person, object or idea, either in public or privately. Praise is typically, but not exclusively, earned relative to achievement and accomplishment...

 offers a momentary personal distraction that can often weaken judgment. Moreover, it is usually a cunning form of appeal to consequences

Appeal to consequences

Appeal to consequences, also known as argumentum ad consequentiam , is an argument that concludes a premise to be either true or false based on whether the premise leads to desirable or undesirable consequences...

, since the audience is subject to be flattered as long as they comply with the flatterer.

Examples:

"Surely a man as smart as you can see this is a brilliant proposal." (failing to accept the proposal is a tacit admission of stupidity)

"I needed a beautiful woman to endorse my product, so naturally I thought of you." (failing to endorse the product is a tacit rejection of being beautiful)

Appeal to flattery is a specific kind of appeal to emotion

Appeal to emotion

Appeal to emotion is a potential fallacy which uses the manipulation of the recipient's emotions, rather than valid logic, to win an argument. The appeal to emotion fallacy uses emotions as the basis of an argument's position without factual evidence that logically supports the major ideas endorsed...

.