Related Clues:

• Initialism after a graphic comment
• "Shush!"
• Letters for someone who overshares
• Sign outside a post office
• "Hit the brakes!"
• Exclamation to a pesky sibling
• 'You're oversharing' in a chatroom
• With 28-Across, like some traffic
• Relative known for quitting?
• ''All right already!''
• "Cut that out!"
• Sam, Vanya or Buck
• Donald Duck, to Huey, Dewey and Louie
• 1979 meltdown site, briefly
• "Go no further!"