bye-byes
noun /ˈbaɪ baɪz/
  /ˈbaɪ baɪz/
Word Originmid 19th cent.: from the sound bye-bye, long used as a refrain in lullabies.
Idioms Idioms 
go (to) bye-byes 
- (British English, informal) used by small children or to small children, to mean ‘go to sleep’