Seems towelling filled with poo, shake a leg! (4,6)
I believe the answer is:
look snappy
'filled with poo shake a leg' is the definition.
I don't know anything about this answer so I can't tell whether it can be defined by this definition.
'seems towelling' is the wordplay.
'seems' becomes 'looks' ('look' can be a synonym of 'seem').
'towelling' becomes 'nappy' (I can't justify this - if you can you should give a lot more credence to this answer).
'looks'+'nappy'='LOOK SNAPPY'
Can you help me to learn more?
(Other definitions for look snappy that I've seen before include "Hurry" , "Shift" .)