How do I make myself more physically, and emotionally affectionate?

I have a struggle not only giving, but accepting all demonstrations of any touching or kissing. Not because I have mental issues, or feel insecure at all! But because I’ve never had a chance to get use to it, or learn to do it. I need to know how to relax and enjoy it, and not tense up, and reject it. I want to feel it, and give it. Just don’t know how.