The most common and most likely answer to this crossword clue is the 2 letter word CS
C
S
Buddy explains!
The straight part
We know that "irritating stuff" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case irritating stuff = cs.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 CS mean?
CS noun- The middle tone in either one of the sets of seven white keys on a keyboard or a set of seven strings on a stringed instrument.