Related Clues:

• ['I can't remember the words...']
• Song syllables
• See 37-Down
• Singing syllables
• Skipping syllables
• In ___ land (spaced out)
• See 41-Down
• Part of a refrain, maybe
• Song bit
• Happy-go-lucky song part
• A chorus line?
• 'I don't know the words' chunk
• 'I forget the words' bit
• Refrain syllables
• Bit of a merry refrain