Toadstool leathers don't actively move from one rock to another. If they contact something, however, they will attach to it.
I'd cut "tiny" off the rock and secure it to another rock where it can get more light, which is what I believe Reefscape is suggesting in his illustration. A single smooth cut with a clean razor blade will be all it takes to remove "tiny" from that rock. Cut it as close to the rock as you can, then use any of the numerous techniques for attaching "tiny" to that shell or a different piece of rock. If possible, I'd suggest removing that entire rock from the tank and cutting "tiny" off outside the tank. I prefer using the wedding viel "netting" with a rubberband to hold leather frags in place while they attach on their own, but there are other methods.
I'd cut "tiny" off the rock and secure it to another rock where it can get more light, which is what I believe Reefscape is suggesting in his illustration. A single smooth cut with a clean razor blade will be all it takes to remove "tiny" from that rock. Cut it as close to the rock as you can, then use any of the numerous techniques for attaching "tiny" to that shell or a different piece of rock. If possible, I'd suggest removing that entire rock from the tank and cutting "tiny" off outside the tank. I prefer using the wedding viel "netting" with a rubberband to hold leather frags in place while they attach on their own, but there are other methods.