The most common and most likely answer to this crossword clue is the 5 letter word BUSBY
I've seen this crossword clue in The Daily Telegraph
B
U
S
B
Y
Buddy explains!

The straight part
We know that "see it on ceremonial occasions" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case see it on ceremonial occasions = busby.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 BUSBY mean?
BUSBY noun- A fur hat, usually with a plume in the front, worn by certain members of the military or brass bands.