The most common and most likely answer to this crossword clue is the 9 letter word CONGENIAL
I've seen this crossword clue in The Times
C
O
N
G
E
N
I
A
L
More clues leading to the result CONGENIAL
- A nice long novel can be relaxing
- Study of chin is agreeable
- Nice to get thicker bags in, pulled up
- Welcoming information in part of UK investing in fuel
- Leave to go, having settled up in good humour
- Cosy conga
- Having similar interests, could be nice to take along rambling
- CONGENIAL
- Set around bit of UK that’s friendly
- Incorrigible, wasting time relaxing
Buddy explains!

The straight part
We know that "relaxing" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case relaxing = congenial.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 CONGENIAL mean?
CONGENIAL adjective- Having the same or very similar nature, personality, tastes, habits or interests.
- Friendly or sociable.
- Suitable to one’s needs.