Possible Clues:

• 'I don't buy it'
• 'Harrumph!'
• "Oh, baloney!"
• 'Codswallop!'
• 'Applesauce!'
• 'Oh, baloney!'
• Exclamation of impatience
• Expression of impatience puts pressure on playwright
• ''Horsefeathers!''
• Pressure dramatist's under, it's said, when impatient