Tea extended after two ducks (6)
I believe the answer is:
oolong
'tea' is the definition.
(oolong is a kind of tea)
'extended after two ducks' is the wordplay.
'extended' becomes 'long' ('long' can be similar in meaning to 'extended').
'after' means one lot of letters go next to another.
'two ducks' becomes 'oo'.
'long' after 'oo' is 'OOLONG'.
(Other definitions for oolong that I've seen before include "Kind of Chinese tea" , "sort of leaves" , "A variety of black China tea with green tea flavour" , "Chinese tea leaves - no logo (anag)" , "oriental tea" .)