I have never been a smoker (never touched a cigarette in my life), but there have been times after going out to eat that I have noticed that strong cigarette smell in my hair or after camping, the strong campfire smell. You know what I'm talking about, right?
In college, when this would happen, I would reach for the dryer sheets and rub it all over my head. In my brain at the time, I thought that it would eliminate the smell, but I realize now that it was just masking it.
I totally should have just used baking soda.
But thinking about that has made me realize this: we can totally use our hair as a diffuser! I mean, why not? If the hair can hold the smell from smoke, surly it can also hold essential oils as well. Sure some of the lighter noted oils may not have a lasting smell (they evaporate much faster), but certainly some of the medium and base notes would stay around. And then think of being able to enjoy that smell all day as you are a human diffuser!
Plus, if you study chakras (which I am just starting to get into myself), when you place an oil on your crown (the 7th chakra), it corresponds to the pineal and pituitary gland. This is related to one's personal spiritual connection to the universe. Blockages manifest as psychological problems. But an open 7th chakra means that the pituitary gland can function properly. The pituitary is important in controlling growth and development and the functioning of the other endocrine glands The pineal gland is responsible for your mood, sleep/wake cycles, and more.
Just think of that as you wonder if applying oils to certain body parts matters.
I still have a good deal to learn about with the chakras, but it is very interesting to find connections to ways that we use the oils instinctively and how they relate to ancient practices.