Possible Clues:

• "That's mildly amusing!"
• One changing in tent for a laugh
• Prepare to drive him, of course? What a giggle!
• The inclusion of three identical points produces a titter
• Prepare to drive him, by the sound of it, with a giggle
• What a giggle to prepare to drive him ungrammatically!
• What a giggle to have thee mixed with ease, perhaps
• Get ready to drive him, by the sound of it? That's a giggle
• By the sound of it where he goes for a drive just for a giggle
• Titter-titter