Composer was up to smothering ecstatic moans in taxi (6,3)
I believe the answer is:
hansom cab
'taxi' is the definition.
(I have seen 'Victorian taxi' mean 'hansom cab' so perhaps 'taxi' could also mean 'hansom cab')
'composer was up to smothering ecstatic moans' is the wordplay.
I cannot really see how this works, but
an anagram of 'moans' is 'ansom' which is present in the answer.
This explanation may well be incorrect...
'in' is the link.
Can you help me to learn more?
(Other definitions for hansom cab that I've seen before include "Taxi forerunner" , "Victorian taxi" , "One used to carry fare" , "Horse-drawn two-wheeler" , "In old vehicle" .)