The most common and most likely answer to this crossword clue is the 5 plus 5 letter word DONER KEBAB
I've seen this crossword clue in The Guardian
D
O
N
E
R
K
E
B
A
B
More clues leading to the result DONER KEBAB
Buddy explains!
The straight part
We know that "conclusion to a boozy night out" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case conclusion to a boozy night out = doner kebab.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.