Related Clues:

• Alternative to a tap
• 'Um, excuse me...'
• Subtle "Hey, you!"
• "If I may cut in ... "
• Sibilant sound to get someone's attention
• Secretive "over here"
• 'You ... over there ...'
• 'If I may interrupt...'
• Bad attention-getter in a crowded bar
• Sound that turns some heads
• Soft "hey, you"
• Sound made with fist-to-mouth
• Quiet "Excuse me"
• Clandestine attention-getting sound
• Sound heard by an exam proctor, say