Question

Here what is the meaning of drooling???​

Answer 1

gerund or present participle: drooling

drop saliva uncontrollably from the mouth.

"the baby begins to drool, then to cough"

synonyms:salivate, dribble, slaver, slobber, drivel, water at the mouth; 

slabber

"his mouth was open and drooling"

Answer 2

Literally, "drooling" is when saliva comes out from the mouth, just like that of a baby.

Here, drooling may mean that they actually enjoyed the training maybe?

I guess that the training seemed interesting or likeable to them.

Hope it helps. :)