Possible Clues:

• 31-Across, e.g
• Catchy pitch
• End of a plug, often
• 'Just do it' or 'Got milk?'
• 'Just do it' or 'I'm lovin' it'
• Lay's "Betcha can't eat just one" is one
• "Beanz meanz Heinz," e.g.
• Brief pitch
• Pithy pitch