Related Clues:

• Make noise in bed
• Produce Zs
• Sleep interruption
• In comics, it's represented by a string of Z's
• Soft palate resonance
• Boring event
• Nighttime noise
• Sound of z's
• Nasal noise
• Bored response
• Real bore
• Sleep sound
• Nap noisily
• Sound of sawing wood?
• Cause someone's insomnia, maybe