Related Clues:

• Get in trouble, in a way, with 'on'
• Serenade
• Do numbers
• Perform in an opera
• Tell (on)
• Be a stool pigeon
• Tell a secret
• Rat, so to speak
• Tell all, slangily
• Do lullabies, e.g.
• Be a squealer
• Give away a secret
• Rat someone out
• Sing in court
• Perform 2-Down