Experience visions of irritations (3,6)
I believe the answer is:
see things
'irritations' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.
'experience visions' is the wordplay.
'experience' becomes 'see' (seeing is a kind of experiencing).
'visions' becomes 'things' (I am not sure about this - if you are sure you should believe this answer much more).
'see'+'things'='SEE THINGS'
'of' is the link.
Can you help me to learn more?
(Another definition for see things that I've seen is " Hallucinate".)