You can take a razor blade and cut the mushroom at the base then put the mushroom in the bottom of a small plastic cup (cut in half and full of lr
) so that it can attach and not get blown away. You could cut it in half when you do this but the less times you cut it the more successful you will be. Like if you just cut it in half, you will be more successful in having them live then cutting them into quarters or eighths. Different species can it handle more then others. I've cut regular discosoma and ricordea yuma with success. The hardest part seems to be keeping them from blowing away in the current. And make sure you put them in at the bottom of the tank in a low flow/ low light area for them to heal.
I've ripped off ricordea yuma and put it on another rock and had the original polyp live and then the parts of the base that I ripped off developed into 3 new ricordeas. But the rock got an infection that spread through the ricordea on the rock and I didn't catch it in time so I only have 4 of those ricordeas now.