after some more research and discussion, digging into many good points brought up around this forum, we've realized that what we're looking for is less of a relationship and more like "friends with benefits," someone (or someones) to play with on occasion. Upon deeper reflection, we're not sure we'd ever be completely comfortable with integrating another person or people into our lives. There are many factors and pitfalls for such things that we hadn't thought of before.
This to me says that they want a FWB which they feel means "someone they play with on occasion". They know they don't want to integrate someone into their lives and will therefore avoid emotional intimacy with that person in order to avoid those sorts of complications. That usually means that they will put up boundaries with the friend(s) they have sex with that they wouldn't necessarily put up with a purely platonic friend.
Ie. Friend without benefits needs somewhere to crash for a few weeks - within realms of friendship. FWB needs somewhere to crash for a few weeks - Little bit different. Bit like letting a new partner you're a little unsure of stay for a few weeks. Might give misleading impression and propel relationship outside of comfort zone.