Imagine you are a tiny ghost and you are sitting on your gave. Around you, you see your ghost dog who was very loyal in life and would never stray very far from your side. He still is very loyal, so never too far away. He generally is closer rather than further from you and most times you both overlap, he likes ghost-strokes. The closer he is to you the happier he is, but every now and again he gets distracted and wanders off a little way. If you imagine your dog leaving behind ectoplasmic drool, after a certain time you would be able to tell where he likes to hang out, right?
Now imagine that you are actually a hydrogen nucleus and your dog is the 1s electron. The ectoplasm represents the time averaged position of the 1s electron.