Why do we call a plushy a Banana Duck, and not a Duck Banana?

The Banana Duck asked to be called that.

It’s probably because of the consonants and vowels in the words and how they run together. Duck Banana puts the hard “k” sound right before the “b” sound. It is not a smooth transition. Banana Duck rolls more smoothly with the softer “a” rolling into the harder “b”

The Banana family descends from a long line of European title aristocrats.

[First of all the royal peeler (names after Sir Robert Peel – that’s how banana peel got its name) peels the banana. Then the royal slicer cuts the banana into the correct 1″ long, ¼″ thick ovals (NOT circles – that’s for commoners). The slices are then laid on a silver salver and HM’s banana inspector checks for brown bits and discards them.]

They were never knights or kings, but members of the royal family were earls and dukes during the 1700s.

They held the honorific title Banana Duke for several generations. Banana Duke George Winthrop had the title from 1773–1844, Banana Duke Edward William had it from 1844–1867, and the last of the Banana Dukes was Mortimer Michael, who had the title from 1868–1901.

Banana Duke was too much of a mouthful, as @seawulf notes. So when the family died off (Mortimer Michael was the last of his family to hold the title) the family was colloquially called the Banana Ducks.

Banana Duck, Banana Duck, Goose!

@seawulf575‘s answer sounds plausible. Also, we may relate more to a thinking creature with personality having botanical attributes, as compared to an inanimate thing having animal attributes.