Always first to get into bar ... which might explain this (4,3)
I believe the answer is:
beer gut
'might explain this' is the definition.
I don't know anything about this answer so I can't judge whether it can be defined by this definition.
'always first to get into bar' is the wordplay.
'always' becomes 'eer' (poetic way of saying ever).
'first to' suggests taking the first letters.
'into' is an insertion indicator.
'bar' becomes 'but' (both can mean 'except for').
The initial letter of 'get' is 'g'.
'eer'+'g'='eerg'
'eerg' going into 'but' is 'BEER GUT'.
'which' is the link.
Can you help me to learn more?
(Another definition for beer gut that I've seen is " large corporation".)