Related Clues:

• Erupt, as Etna
• Emit like a volcano
• Do a double-take, e.g.
• Jet forth
• Respond to stimulus
• Burst forth
• Express feelings
• Answer back
• Eject forcefully
• Pour forth
• Eject forcibly
• Jerk one's knee, perhaps
• Say ''ouch!'' when pinched, e.g.
• Punch back instinctively
• Do a double-take