Experiment
Right now, Shion happens to be thirteen years old. He's a bit different than he is when he's older, including having less of a concept of privacy. He's also convinced that whatever he's doing is right, that he knows best, and that he can do no wrong....basically he's a stubborn teenage boy who thinks he's special. One with a lot of psychic power that he isn't shy about using, particularly when he's frustrated or not getting what someone is trying to tell him. So, that being said, it would help if you would answer a few questions:
Is it all right for Shion to poke around in your character's head? Is there something that you really, really don't want him to find? Is there a reason that Shion wouldn't be able to read your character's mind?
Keep in mind that Shion is still a rather inexperienced kid right now. Any sort of mental block or shield will likely stop him from being able to do anything.