Ball fits in tiny piece of furniture (7)
I believe the answer is:
tallboy
'piece of furniture' is the definition.
(tallboy is a kind of piece of furniture)
'ball fits in tiny' is the wordplay.
'fits' is an anagram indicator.
'in' is an insertion indicator.
'tiny' becomes 'toy' (I can't justify this - if you can you should give a lot more credence to this answer).
'ball' anagrammed gives 'allb'.
'allb' going within 'toy' is 'TALLBOY'.
Can you help me to learn more?
(Other definitions for tallboy that I've seen before include "Big chest of drawers" , "Chest of drawers mounted on legs for lofty youth" , "Chests of drawers, one on top of the other" , "Item of furniture" , "Type of chest of drawers" .)