Ok so how does one activate the sharingan eye. I know you get it by experiencing something dramatic. But how do you activate it. It’s off a lot of the time but when in battle the guy says sharingan in his head and his eye transforms but HOW. Jojo says that the stand summon because of a fear or something else. But how do you activate it. Is it like an extra muscle like how you move your arm like you just know. This just confuses me.