mouthwatering might have come by conditioning ,because the response to the stimulus becomes associated with the other causing "mouthwatering".
The waiter placed a mouthwatering meal in front of a group of ravenous customers, and immediately regretted it.
mouth watering
Similie. When you use like or as that is a smilie. :)
i think James said in the book twilight, that Alice had very mouthwatering blood.
Metaphor
It is a similie as you are comparing (something) to how sly the fox is. A similie uses the words "like or "as".
Yes, "mouthwatering" is an adjective used to describe food that looks or smells delicious and makes one's mouth water in anticipation of tasting it.
two
Weak as a kitten.
As clean as a whistle.
As dry as a bone.