Massage therapists and aestheticians are encouraged to offer their clients an oxytocin release along with their treatments in this article from Skin, Inc. This seems to be a very good trade magazine for spa professionals. Writer Irina Brown points out that it's as good for the giver as for the receiver:
The good news is that it is not only the person on the receiving end of “touch therapy” that benefits from oxytocin release. Studies show that the person administering “touch” also experiences heightened levels of oxytocin. Massage therapists exhibit the typical effects of high levels of oxytocin, such as lower levels of stress hormones and lowered blood pressure, according to Kerstin Uvnas Moberg, MD, author of The Oxytocin Factor (Da Cappo Press, 2003).
In fact, I don't believe there are any studies at all showing that a person being massaged has higher oxytocin levels, although it seems intuitively correct. But there are studies showing the masseur or masseuse has higher levels post-massage.