A good set of drinks on the rocks? (7)
I believe the answer is:
aground
'on the rocks?' is the definition.
(I've seen this before)
'a good set of drinks' is the wordplay.
'good' becomes 'g' (abbreviation).
'set of drinks' becomes 'round' (as in a round of drinks ordered at a bar).
'a'+'g'+'round'='AGROUND'
(Other definitions for aground that I've seen before include "(Of ship) touching the bottom" , "On guard (anag.)" , "out of water" , "No longer floating" , "Beached" .)