Mindreader?

Wouldnt it be nice if people could read your mind? But only when you wanted them to. Not all the time- haha that would be very problematic for me. No, only when you wanted to say something but couldn't, or were too scared to. People, more specifically a person, could just KNOW what you wanted them to know. Maybe I'll invent a button that does that? Or if someone else wants to invent one let me know and I'll jump on the bandwagon.