Lager drunk after spirit, drinker's penultimate drink (6,3)
I believe the answer is:
ginger ale
'drink' is the definition.
(ginger ale is a kind of drink)
'lager drunk after spirit drinker's penultimate' is the wordplay.
'drunk' is an anagram indicator.
'after' says to put letters next to each other.
'spirit' becomes 'gin' (I've seen this before).
'drinker's penultimate' becomes 'e' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'lager' is an anagram of 'geral'.
'geral' put after 'gin' is 'gingeral'.
'gingeral'+'e'='GINGER ALE'
Can you help me to learn more?
(Other definitions for ginger ale that I've seen before include "Fizzy drink" , "It won't make you drunk!" , "Spicy, sweetened non-alcoholic drink" , "One drink" , "pop" .)