From Melanie Klein, The Psycho-analysis of Children --
The form in which interpretation is given is another thing of great importance. It should be modelled on the concrete way in which children think and speak. Peter, it will be remembered, pointed to the swing and said: 'Look how it dangles and bumps'. And so when I answered: 'That's how Daddy's and Mummy's thingummies bumped together', he took it in without the slightest difficulty. To take another instance: Rita (aged two and three-quarters) told me that the dolls had disturbed her in her sleep; they kept on saying to Hans, the underground train man (a male doll on wheels): 'Just go on driving your train along'. On another occasion she put a triangular brick on one side and said: 'That's a little woman'; she then took 'a little hammer', as she called another long-shaped brick, and hit the brick-box with it exactly in a place where it was only stuck together with paper, so that she made a hole in it. She said: 'When the hammer hit hard, the little woman was so frightened'. Running the underground train and hitting with the hammer stood for coitus between her parents, which she had witnessed till she was nearly two years old. My interpretation, 'Your Daddy hit hard like that inside your Mummy with his little hammer, and you were so frightened', fitted in exactly with her way of thinking and speaking.