Sometimes, you have a couple things, right? You'd like one of those things to spin...but you don't wanteverything to spin. Friend, do I have a 3d print for you.

These rings are 14mm ID - feel free to scale everything up if you want a chonkier swivel. (If you can scale them down, good on you, but this is just about as small as I can manage.) Everything has a flat surface that you should lay flat on the bed, as shown.

I don't know how to say this emphatically enough: if a person is going to be standing on or under a thing that might hurt them if it fell, do not use this to hold that thing up.