I have been drawing names on my kids' lunch bags since they started carrying lunch to school in first grade.
There are a few rules which apply when it is convenient: the idea is usually the first thing I think of when I wake up, the drawing must be finished before we leave for school after the sandwiches are made and everyone is fed and dressed, and it should contain his name at least once, but it is often hidden in the picture many times. The images often refer to daily events, homework, the books we are reading, or the nature and mystery of peanut butter and jelly.