With extra glass and large drink, took it easy after golf (6-6)
I believe the answer is:
double-glazed
'with extra glass and' is the definition.
I can't tell whether this definition defines the answer.
'large drink took it easy after golf' is the wordplay.
'large drink' becomes 'double' (I've seen this before).
'took it easy' becomes 'lazed' (I can't explain this - if you can you should believe this answer much more).
'after' means one lot of letters go next to another.
'golf' becomes 'g' (phonetic alphabet: alpha, bravo, charlie etc.).
'lazed' put after 'g' is 'glazed'.
'double'+'glazed'='DOUBLE-GLAZED'
Can you help me to learn more?
(Other definitions for double-glazed that I've seen before include "Two panes thick" , "Like many windows" , "With a further set of windowpanes" .)