Through touch you and your partner keep an emotional connection. A hormone, Oxytocin, which is also referred to as a bonding hormone, is released when you touch. Oxytocin is not only bonding, it also reduces your stress level so your cortisol levels decrease. Just because your partner touches you doesn't mean that it's a romantic touch. Touches that linger for more than a few seconds and feels like a caress signals a romantic touch. Also, if they use their hand versus their fingertips when they touch signals romantic interest as well.
When a man touches the small of a woman's back, if usually signals that he's being protective and it's a sign that she's taken. So onlookers should look elsewhere. Touching the small of a woman's back also allows for the man to get physically closer to this woman. He can also guide the woman through a crowd by applying different pressure using his fingers on her back. The gentle pressure gives her silent clues to where to walk.
Share your thoughts on my Facebook page: Blanca Cobb-Body Language Expert. While you're on my page, give it a "like". Write a message on my timeline and I'll get back to you.