And not small when unwrapped, as usual (6)
I believe the answer is:
normal
'as usual' is the definition.
(I've seen this before)
'and not small when unwrapped' is the wordplay.
'and not' becomes 'nor' ('nor' means 'and also not').
'when unwrapped' says to take the centre (the word is unwrapped or uncovered).
The centre of 'small' is 'mal'.
'nor'+'mal'='NORMAL'
(Other definitions for normal that I've seen before include "Unremarkable" , "'Usual, typical (6)'" , "Usual; at right angles" , "Usual - sane" , "Standard; at right angles" .)