The most common and most likely answer to this crossword clue is the 8 letter word RATAPLAN
I've seen this crossword clue in The Times
R
A
T
A
P
L
A
N
More clues leading to the result RATAPLAN
Buddy explains!
The straight part
We know that "tattoo" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case tattoo = rataplan.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 RATAPLAN mean?
RATAPLAN noun- A continuous, even drumming or rapping, as of the hooves of a galloping horse, or machine-gun fire.
- To drum repeatedly.