Releases yob that keeps drug stash regularly hidden (4,3)
I believe the answer is:
lets out
'releases' is the definition.
('let out' can be a synonym of 'release')
'yob that keeps drug stash regularly hidden' is the wordplay.
'yob' becomes 'lout' (I've seen this in other clues).
'that keeps' indicates putting letters inside.
'drug' becomes 'e' (E is another name for ecstasy).
'regularly hidden' indicates alternate letters (letters removed at regular intervals).
The alternating letters of 'stash' are 'ts'.
'e'+'ts'='ets'
'lout' placed around 'ets' is 'LETS OUT'.
(Other definitions for lets out that I've seen before include "Discloses" , "rents" , "Reveals" .)