Sorry I don’t have a stake in this question, but what does “fall into more than two” mean?
More than two people in bed.
Good lord, speak plainly.
That’s more of a swingers thing than a poly thing.
In the vast majority of poly relationships, people are in separate relationships with each of their partners.
Triads (and quads, etc) are hard-mode. They certainly exist, but they take skill and effort from everyone involved, and so are significantly more rare. And of those, probably only a minority are going to be into the whole group-sex thing in the first place so… not very often.
I tried it. Basically all the time. Turned out to be a nightmare pretty quick. Don’t recommend unless you have exceptional communication skills and a lot of self confidence.
Why don’t you tell us your background & context, the ones that make you ask this question?
Yeah without any stated stake in this, this seems to be just looking for free smut to read. This isn’t the place.