Drop duck, seeing rude behaviour when serving hummus (6,3)
I believe the answer is:
double dip
'rude behaviour when serving hummus' is the definition.
I know nothing about this answer so I can't judge whether this works.
'drop duck' is the wordplay.
'drop' becomes 'double' (I can't justify this - if you can you should give a lot more credence to this answer).
'duck' becomes 'dip' (both can mean to plunge into water).
'double'+'dip'='DOUBLE-DIP'
'seeing' is the link.
Can you help me to learn more?
(Other definitions for double dip that I've seen before include "In America, maybe moonlight" , "type of recession" .)