Possible Clues:

• Little laughter
• 'More of 27 across, perhaps, to make one laugh (6)'
• Laugh s little at the non-drinker in the row
• Stifled giggle
• Snigger
• Self-conscious laugh
• Giggle where teetotaller in row
• Suppressed guffaw
• How hilarious to find a motor race in the middle of a row like this!
• Internet feature out west is a bit of a laugh