Gloat (5)
There are a few possibilities for this:
rub it in
(Other definitions for drool that I've seen before include "Dogs may" , "dribble" , "Slaver - drivel" , "Salivate" , "Let saliva run from the mouth" .)
'gloat' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for exult that I've seen before include "Rejoice intensely" , "Show triumphant joy" , "Crow in triumph" , "Show triumphant elation" , "Show jubilation" .)
'gloat' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for rub it in that I've seen before include "Continue to remind one of a mistake" , "Harp on something distasteful to person not wishing to be reminded of it" , "Harp on to someone about something of which he does not wish to be reminded" , "Remind someone maliciously of an embarrassment" , "Remind person of unpleasant fact - during massage?" .)