Possible Clues:

• Boost the horsepower of
• Get on the wagon
• "Jump into Daddy's lap!"
• Invitation to a dog while patting the bed, perhaps
• Make more powerful, so to speak
• What you might have to do to sit on a barstool
• ''Jump into Mommy's lap!''
• ''Jump into Daddy's lap!''
• Amplify, informally
• Amplify, so to speak