What does the Japanese onomatopoeia もきゅもきゅ mean?


I heard this in a Japanese song sung by Vocaloid Hatsune Miku
([YouTube](https://www.youtube.com/watch?v=CkYbNnGe2Ik))

Does anyone know what this onomatopoeia means? It's clear from the context of
the lyrics that it is an onomatopoeia, but I've never heard it used before.

For context, the lyrics say:

> ホッペタを少し膨らませて  
>  I’ll puff out my cheeks and go
>
> モキュモキュにしてやるぞ  
>  “mokyu mokyu” just for you, OK?
>
> アヒルみたいな唇をして  
>  I’ll make duck lips and go
>
> モキュモキュにしてやるぞ  
>  “mokyu mokyu” just for you, OK！




It means "cute (and fluffy)".

Imagine a hamster stuffing its face with food.

