Related Clues:

• Start of a library conversation
• Attention-attracting sound
• Quiet "Over here!"
• Hushed head-turner
• Alternative to "ahem"
• Secretive attention-getter
• Subtle call for attention
• Alternative to an elbow
• Test cheater's sound
• Relative of 'Hey, ma'
• "Hey, listen up!"
• Quiet supersonic transport is an attention grabber
• Call for attention from vessel in training
• Way to support rider over here!
• Hissing noise to attract attention