Possible Clues:

• Words spoken with a yawn, perhaps
• Comment before retiring
• 1959 top 10 hit for Ricky Nelson
• 'I should turn in'
• ''Gotta go now!''
• ''I really should be going''
• Words said while stretching, maybe
• "Oof, look at the time"
• 'I should hit the hay'
• "Gosh, look at the time"