Thinking with your head generally refers to "Logic" in thought processes rather than thinking emotionally.
It means to understand what you are thinking, to empathize.
"Dive in head first" is to rush into a situation without thinking.
"My head is on my shoulders" means they are thinking right, they have their head in the right place.
That all depends are what you're thinking. If they are innocent thoughts, probably so. Congratulations!
Thoughts aloud means when you are acting the person says what they are thinking from their head.
That means you reacted to something negative without thinking first.
thinking is more important than physical activity
"On my mind" means you are thinking of the person or thing, as if it were literally inside your head sitting on your mind.
It means that you are putting some time and effort into what you are thinking about. It isn't the first thing that pops into your head.
It means they're thinking about you instead of what they're supposed to be thinking about. This term is sometimes used before sporting events if one participant is trying to psych out the other.
Thinking?
It mean's your brain was thinking about fish while falling asleep and focused on it.