Possible Clues:

• 'I should be going'
• Words just before leaving
• 1959 Ricky Nelson hit
• 'I really should be going'
• Words said while stretching, maybe
• Reason for leaving
• Lead-in to 'I really should get going'
• “Gotta go!”
• Yawner's comment, perhaps
• Words spoken with a yawn, perhaps