The most common and most likely answer to this crossword clue is the 4 plus 2 letter word ROLL UP
I've seen this crossword clue in The Guardian
R
O
L
L
U
P
Buddy explains!
The straight part
We know that "Come/smoke" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case come/smoke = roll up.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 ROLL UP mean?
ROLL UP adjective- Capable of being made into a cylinder shape by rolling.
- Food made by wrapping ingredients in another food, e.g. fajitas.
- A self-made cigarette of tobacco and rolling paper.
- A business technique where multiple small companies in the same market are acquired and merged.
- A collection of software updates distributed as a single package.
- That which is rolled up; a summation; an aggregation; a total.