The most common and most likely answer to this crossword clue is the 9 letter word TATTOOING
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Buddy explains!

The straight part
We know that "parlour activity" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case parlour activity = tattooing.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 TATTOOING mean?
TATTOOING verb- To apply a tattoo to (someone or something).
- To hit the ball hard, as if to figuratively leave a tattoo on the ball.
- To tap rhythmically on, to drum.
- The act of beating out a rhythm on a drum
- The act of marking the skin with a tattoo