The most common and most likely answer to this crossword clue is the 7 letter word CUMULUS
I've seen this crossword clue in The Daily Telegraph
C
U
M
U
L
U
S
Buddy explains!
The straight part
We know that "a fluffy wet type" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case a fluffy wet type = cumulus.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 CUMULUS mean?
CUMULUS noun- A large white puffy cloud that develops through convection. On a hot, humid day, they can form towers and even become cumulonimbus clouds.
- A mound or heap.