Out of practice, one gets hammered drinking this (5,4)
I believe the answer is:
rusty nail
'drinking this' is the definition.
I know nothing about this answer so I cannot tell whether this works.
'out of practice one gets hammered' is the wordplay.
'out of practice' becomes 'rusty' ('rusty' can be a synonym of 'out of practice').
'one gets' is a charade indicator (letters next to each other).
'hammered' becomes 'nail' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'rusty'+'nail'='RUSTY NAIL'
Can you help me to learn more?
(Other definitions for rusty nail that I've seen before include "one's likely to get hammered!" , "one drunk at cocktail party?" , "Strong sweet cocktail" .)