She seems to love....?

Long story short I Got my long hair and beard shaved I mean it used to be like Dave Grohl with a bigger beard. When I got it cut a girl I like felt my head and discovered a spot just on the back of it which feels amazing when rubbed since before I can remember. Ever since she will use any opportunity to rub that bit. For example I'll sit next to her and shell start rubbing it or shell just randomly come up behind me to get at my head. One time I think she used it as a ploy to get a tighter hug from me. I was hugging her normally and she touches the spot which causes me to put my head in her neck/collar to escape and the fright caused me to instinctively squeeze tighter. She held the hug a bit longer then let me go. I like her and I think she likes me but WTF is up with her and that spot on my head?