Young children depend on adults around them to make the world safe. They are forming their knowledge of the world by matching words to the those things that they see. They also match the mood of the moment that is conveyed by the adult who is with them.
If the trusted adult offers a happy/playful mood and attaches it to behavior that is creepy then the child will become confused, because the emotion she feels doesn't match the emotion of the adult she trusts. This is especially true when the adult makes a game out of something that does not feel like fun and the child is asked to participate, and join in the game even if it doesn't feel like a game.
These behaviors haunt us as we become adults who don't trust our emotions and find confusion in the mismatch between what we feel and what we remember when working through difficult issues in therapy.