The most common and most likely answer to this crossword clue is the 8 letter word IMBIBING
I've seen this crossword clue in The Times
I
M
B
I
B
I
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G
Buddy explains!

The straight part
We know that "Drinking" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case drinking = imbibing.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does IMBIBING mean?
IMBIBING verb- To drink (used frequently of alcoholic beverages).
- To take in; absorb.
- The act by which something is imbibed.