You are not wrong, at all, for asking for what you need. At first, with my friends, it took a little bit for them to get used to it. Now, they all ask before going in for a hug or wait until I initiate the touch. Also, I had a couple people at first touch me and then realize and apologize. They had the same thoughts as your friend, but when I stuck to it, they realized I was serious and it really did affect me differently.