The Law of the Subway dictates that each straphanger occupy exactly one (1) seat, regardless of bags, specialized Popeyes tables or any other accoutrement that may be accompanying you on your journey. Special exceptions can be made during non-rush hour traveling times, but in general, your body and everything attached to/dangling from it should be condensed into that one (1) seat.
It should go without saying this also applies to your remarkably long locks. The proper way to commute with such a coif is to pile it up on top of your head, wrap it around your body like the bandages on a mummy/sheets on a toga party attendee, or fold it into your lap like a pet.
Your hair, while very beautiful, does not need to cascade down the backside of the seat behind you, and it especially does not need to stretch out into the seat beside that one.
Somewhere nearby, an elderly woman's arthritic knees are probably buckling or a toddler is about to commence in a long, sustained symphony of shrieking. Your hair doesn't have arthritis or vocal cords. It does not have needs or feelings at all. Please move it.
For more of our ongoing subway etiquette coverage—including our hard-hitting manspreading reportage—click over here.