Childish farewells uttered close to extras (3-4)
I believe the answer is:
bye-byes
'childish farewells' is the definition.
'bye-byes' can be an answer for 'farewells' (bye-bye is a kind of farewell). I am not sure about the 'childish' bit.
'uttered close to extras' is the wordplay.
'uttered' indicates a 'sounds like' (homophone) clue.
'close to' becomes 'by' (close by).
'extras' becomes 'byes' (I've seen this before).
'by' sounds like 'bye'.
'bye'+'byes'='BYE-BYES'
Can you help me to learn more?
(Other definitions for bye-byes that I've seen before include "Sleep for little children" , "(Child's word for) sleep" , "Informal repetitive farewells" .)