Useful term which I hadn't heard (or at least not remembered) before. Thanks. In a similar vein, I guess one could talk about "service bottoming".
Some (French?) philosopher from a few centuries ago (18th century?) pointed out and discussed that we can choose what we do ("free will") but not what we want to do (or what we like, enjoy, desire...). I'm blanking on the name. Anyone know? In any case, an interesting point and distinction. In current pop cultural terms, I think this is what people mean when they say "The heart wants what the heart wants", indicating that someone has no control over what they want.
-Ww
Yes, there are service bottoms I suppose, there are also "power bottoms" (which is also a term used outside of BDSM with just the gay community but they're similar contexts) where it's someone who is usually Dominant wanting things to be done to them that normally are done to someone submissive, they're still in command or control, even if they're the ones having certain acts done upon them.
I suppose a context here is that there are sex acts that can be seen as being a part of BDSM, and then there's the ritualistic BDSM (Like
@TheScientist points out) people can do or have various BDSM like sex acts done to them without falling into a D/s or S/m category, a little spank and tickle in the bedroom doesn't make you a Dom or a sub. And of course we may do a lot of those things because they heighten pleasure or they're just something our partner likes to spice things up a little here and there, so it doesn't make you a Dom/sub/or switch to be able to do or accept these things.
Within the ritual or "I have an actual fetish for this" BDSM that's where the whole "Heart wants what it wants" issue comes up, if you are a Dom it's something that just comes naturally to you, there's the urge there to do it, that is what you want and like and brings you pleasure.
Same with being a sub, you crave those things because beyond logic or reason it just feels right to you.
And with being a switch it's really just that there are some parts of you, with certain people, where certain urges will arise, and some parts of you, with other people, where other urges arise. Making yourself go one way or another would be like eating cake everyday, it's great for a while but then you get sick of it, so you crave that variety.
You can lean to do the BDSM acts, learn Shibari and how to tie, learn how to train someone as a panty slave, there are lists of scenes that you can use as a jump point to create things, much like you can lean to DM in D&D, but if you don't like it it won't be intuitive and you're not going to be having fun, you'll just be following some script.
In that aspect it's harder to be a submissive, because it's difficult to learn to force yourself to play along with someone else's fantasy, to allow yourself to be humiliated, or hurt, or to act a certain way if you're really not into it. Not only is it not intuitive or enjoyable for you, but unlike being a Dom, a subs reactions can't be pre-scripted.