Harassed teachers lie when confiscating small firework (9,5)
I believe the answer is:
catherine wheel
'firework' is the definition.
(Catherine wheel is an example)
'harassed teachers lie when confiscating small' is the wordplay.
I cannot quite see how this works, but
an anagram of 'when' is 'newh' which is present in the answer.
This may be the basis of clue (or it may be nonsense).
(Other definitions for catherine wheel that I've seen before include "sparkling ring" , "Rotary firework" , "revolver" , "Spinner producing spectacular display" .)