When my now 40 year old son was 3, I was pregnant with my older daughter. I was always generously endowed, and pregnancy made it much more obvious. The buttons on my favorite blouse popped open under the strain. My sweet little boy happened to look over at just the right time. He innocently asked me what those things were for? So I told him the truth, that when the baby was born they would make milk for the baby to eat. He looked at me like I was crazy and said, " Awwww...C'mon! Tell me the truth!"
Then there was the time he wanted me to buy him something. I told him I didn't have the money to buy it because I really didn't have the money. He thought about that for a minute, and then replied, "Well, take Grammy's purse. She has money!"
I could go on and on...