The most common and most likely answer to this crossword clue is the 4 plus 1 plus 4 plus 3 plus 5 plus 5 letter word MAKE A SONG AND DANCE ABOUT
I've seen this crossword clue in The Guardian
M
A
K
E
A
S
O
N
G
A
N
D
D
A
N
C
E
A
B
O
U
T
Buddy explains!
The straight part
We know that "Fuss over" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case fuss over = make a song and dance about.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.