Massage operates in a continuum between physical therapy or say
Shiatsu, which is exclusively muscle focused and is highly non-erotic, to
Swedish massage, which is muscle focused and includes affectionate but not
erotic touch, to erotic massage which is a sexual technique.
        Most people's response to a good (Swedish) massage is to fall
asleep, not to get aroused.  If a massage is focused on relaxing muscle
groups, it will not be an erotic experience.  The donor will get a major
workout and the receiver will be very relaxed.  If a massage is focused on
touching skin it will be an affectionate experience and a highly intimate
and emotional one -- but not an erotic one.  If a body rub is primarily
focused on touching skin, especially if that focus includes erogenous
zones, it may be an erotic experience.
        There are some very nice strokes which are used only in sexual
contexts, they are quite distinct from the strokes used in other kinds of
massage.  Some of them are described in the archive.
        One of the hallmarks of a dysfunctional family (one which
perpetuates a culture of addiction and dependence) is a deep confusion
between affectionate and erotic touch combined with a strong yearning for,
yet fear of, emotional intimacy.  People who have this confusion are likely
to experience any kind of touch as erotic or to use affectionate touch as a
surrogate for forbidden erotic touch.  These same people are likely to view
all nudity as sexual, or more properly, to consider touch, nudity and sex,
as surrogates for the intimacy vacuum associated with the culture.  This
forms the subtext for some of the threads that appear periodically in the
newsgroup.  Because most massage, like most body therapies, is hindered by
clothing, and involves touch, this newsgroup periodically attracts the
attention of some of these unfortunates.
        You will avoid unpleasant misunderstandings if you are clear in
your own mind on what you want, and if you are able to clearly discern
between a prospective masseur/masseuse/massee :-) and a prospective sexual
partner, or someone with a voyeuristic interest in the pseudo-intimacy of
nudity.
        There is lots about this in the archive (see question 5.1.2 for
information about the archive).  In particular, see the sections entitled
`Sex & Massage' and `Sexual Massage/Foreplay'.