Related Clues:

• Sound from a test cheater, say
• Confidential warning
• 'Don't tell anyone, but...'
• Hushed ''Hey!''
• Classroom nudge
• Sibilant call
• Subtle signal
• Verbal elbow?
• Subtle "Over here!"
• Start of a library volume discussion?
• "Yo, over here!"
• Hissed nudge
• Furtive "Yo!"
• ''Over here''
• Alternative to 'Yo!'