When my niece (who is my godchild) was small, probably around three years old, she had been use to catching fish because my brother had a camp on a lake and always took her fishing. She loved to go and was good at it. They caught a lot of sac a lait, bream and bass. Well she was sitting on my brother in law's lap one day and he was flipping thru an outdoor magazine looking at the pictures. He would point to a picture and ask, What's that. Her reply, a squirrel! What's that? A rabbit. What's that? A deer! What's that? Her reply caught him off guard, a sac a day. He was expecting "a fish" but she had caught so many "sac a day" she new what one looked like. From then on, that's what my brother and I call them sac a day.