Bring out party drug (legal) (6)
I believe the answer is:
elicit
'bring out' is the definition.
(to elicit is to bring out or call forth)
'drug legal' is the wordplay.
'drug' becomes 'e' (E is another name for ecstasy).
'legal' becomes 'licit' (similar in meaning).
'e'+'licit'='ELICIT'
'party' is the link.
(Other definitions for elicit that I've seen before include "Draw out from, invoke" , "'Draw out, evoke (6)'" , "Brings something out into the open" , "Bring to light" , "Call forth, educe" .)