My children were given a cute VBS CD by their grandparents (SBC). The first song's title is "God's Promises are True," and the kids are actually quite fond of it. It has been ironic to use as a tool to teach the kids about God's Covenant promises contained in the Sacraments.
One of those promises is the promise of Christ's satisfaction for sin in the Lord's Supper. The sacrament is not only a memorial of what God has done through Christ, but also a promise to us of its assurance. The Heidelberg Catechism puts it this way,
"As surely as I see with my eyes the bread of the Lord broken for me and the cup shared with me, so surely his body was offered and broken for me and his blood poured out for me on the cross." - Heidelberg Catechism Q&A 75
John Calvin even more forcefully put it this way in his synchronized commentary of the Synoptic Gospels,
"By the words for you, as related by Luke — Christ directly addresses the disciples, and exhorts every believer to apply to his own advantage the shedding of blood. Therefore, when we approach to the holy table, let us not only remember in general that the world has been redeemed by the blood of Christ, but let every one consider for himself that his own sins have been expiated." - Calvin, Commentary on Matthew, Mark, Luke Vol 3
Holding the bread and wine in service, we quietly remind the children that their "own sins have been expiated." Now we tack on "God's Promises are True" and the little sinners in our family smile.