Completely wrap a small duck's walk (7)
I believe the answer is:
'completely wrap' is the definition.
'swaddle' can be an answer for 'wrap' (I've seen this in another clue). I am unsure of the 'completely' bit.
'a small duck's walk' is the wordplay.
'a small duck's' becomes 's' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'walk' becomes 'waddle' (waddle is a kind of walk).
Can you help me to learn more?
(Other definitions for swaddle that I've seen before include "Bind tight with clothes", "Wrap with bandages", "Fully cover", "Wind bandages round", "Wrap in cloth".)