Bondage deals with tying people up.
(or being tied up)
Or chaining them up,
or restraining them with
straps, or straightjackets, or ...
well, you get the idea.
In theory it can be enjoyed
simply for its own sake --
the sensations and images of it.
In fact, some people do enjoy
bondage as bondage,
without any interest in D&S or S&M,
but far more people find
it pushes their D&S buttons
at the same time,
or use it only for the D&S aspects,
or combine it with D&S and/or S&M.
Dominance and submission
deals with exchange of power,
trust, obedience, role-playing,
"slavery" ...
one person submitting
to the commands of another.
Like bondage,
it can exist as a separate phenomenon,
but it's likely to incorporate the others.
Bondage may be used to enhance
the feeling of submission.
Pain-play (i.e. S&M)
may be used to emphasize
the position the submissive is in
or as punishments for disobedience.
S&M sort of stands for "sadism and masochism",
but not quite the same way the psychiatric
establishment uses those terms.
So it's less confusing
to keep the phrase tidily together as "S&M".
S&M involves strong sensations.
It's associated with pain, in particular,
in most people's minds,
but in fact pain
is only one class of sensations used.
Furthermore, some stimuli
which would ordinarily be perceived as
pain are not perceived as pain by some participants
when in an S&M headspace!
(Note that I said "some".)
While I don't have statistics on this,
it's my impression that S&M is the one phenomenon of
these most likely to occur without the others.
Nonetheless, it is quite common
for one's interest in S&M
to be in the context of bondage or D&S
(the pain makes it so very much clearer
that one can't get away
because one is tied up, for example)
or simply _alongside_ an interest in bondage and/or D&S.
Interestingly, while most "vanilla"
(i.e. not-into-BDSM)
people do not consider tickling
to be a BDSM activity, many BDSM folks do.
More terminology
Some people like to tie people up,
whip people, or give orders.
Others like to be tied up, like to be
spanked or whipped, or like to obey.
Because so many of the words
one might use to describe these
preferences seem specific
to just one aspect of BDSM,
push people's buttons,
or only fit the ways some people play,
folks in the scene use the generic terms
"top" and "bottom".
(Note that these words have a different meaning
in gay male culture, if I'm not mistaken.)
In bondage, a top likes to tie up bottoms.
In S/M, a top likes to provide strong stimulation
(pain or otherwise) to a bottom.
In D&S, a top orders or controls a bottom.
A "switch" is someone who enjoys
being both a top and a bottom.
Note that it's not always the top
who's in control of things --
in fact, much less often than the other way around!
For example, a bottom might ask to be tied up,
and his or her top
might decide to honour thatrequest,
asking the bottom if there were any particular things
he or she wanted the top to do to him or her tonight.
Also, many people use "safewords",
code phrases that mean, "I'm not just playing,
I really need you to stop."
If a couple uses a safeword,
the bottom can stop the current activity
by using the safeword.
Some people claim that the bottom
is always the one who's really in control,
no matter how things look.
They're mostly right,
but things can get more complicated.
