Confession of one fancying men and women in poetic pieces (5)
I believe the answer is:
iambi
'poetic pieces' is the definition.
(plural of iamb, a type of metrical foot in poetry)
'confession of one' is the wordplay.
'confession' becomes 'iamb' (I am not sure about this - if you are sure you should believe this answer much more).
'of one' becomes 'i' (I've seen this in other clues).
'iamb'+'i'='IAMBI'
'fancying men and women in' acts as a link.
This may not be right. Some or all of it may belong to another bit of the clue.
(Other definitions for iambi that I've seen before include "Short-long metrical feet" , "Concierto de Aranjuez composer" , "Feet of two syllables (one short and one long)" , "Metrical patterns" , "Film theatre" .)