With gin and ale getting sloshed is nice (9)
I believe the answer is:
congenial
'is nice' is the definition.
(thesaurus)
I can't explain the rest of the clue.
Can you help me to learn more?
(Other definitions for congenial that I've seen before include "Suited to one's taste" , "Harmonious and friendly" , "Having similar interests" , "relaxing" , "Pleasant and agreeable" .)