Treat pet with trip to resort with gentle sounds (6-6)
I believe the answer is:
pitter-patter
'gentle sounds' is the definition.
'treat pet with trip to resort' is the wordplay.
'with' is a charade indicator (letters next to each other).
'to resort' is an anagram indicator.
'treat'+'pet'='treatpet'
'treatpet' put after 'trip' is 'triptreatpet'.
'triptreatpet' anagrammed gives 'PITTER-PATTER'.
'with' is the link.
(Other definitions for pitter-patter that I've seen before include "Quick, light tapping sounds" , "Sound of little feet" , "Sound of rain or tiny feet" , "Sound of light steps" , "Sound of raindrops" .)