This Little Piggy's Book of Manners by Kathryn Madeline Allen, illustrated by Nancy Wolff

There must be better books of manners, but parents might find this one helpful.

From chapters.ca:
It's easy for young children to sometimes forget their manners, especially when there are so many to remember-'close your mouth while eating,' 'always say please and thank you,' 'share your toys.' What might happen, then, when an occasional manner gets forgotten? CHAOS! And that's putting it mildly. Here's a refreshingly jaunty picture book that will make the experience of learning manners more fun than ever imagined.