Mummy's boy switching tops on delicate fabric cleaner (7)
I believe the answer is:
milksop
'mummy's boy' is the definition.
(both can mean a timid person)
'on delicate fabric cleaner' is the wordplay.
'on' is an insertion indicator (as in clothing 'on' a person).
'delicate fabric' becomes 'ilks' (I am not sure about this - if you are sure you should believe this answer much more).
'cleaner' becomes 'mop' (something which 'cleans').
'ilks' put into 'mop' is 'MILKSOP'.
'switching tops' is the link.
This may not be right. Some or all of it may be part of another bit of the clue.
(Other definitions for milksop that I've seen before include "Wimpish fellow" , "Unmanly man" , "Feeble ineffectual man" , "(Young) wimp" , "He shrinks from" .)