The premise of the books is that each of us has an individual bucket inside of us (self-esteem). When our bucket is full, we feel good about ourselves. When our bucket is empty, we feel sad. We can help fill each other's buckets by saying or doing nice things. We also use the phrases "bucket filler" and "bucket dipper" to describe actions in the classroom and on the playground.
There is a class bucket on the bulletin board near the door. Students are encouraged to write compliments to one another and place them in the bucket. At the end of the week, we read the compliments aloud and take them home.