Just don't cut it in the tank if at all possible, if you have to be sure you are running carbon
Typically fragging them you cut a circle around the top, try to keep it even so it doesn’t grow oddly. I have also cut a arch only on one side in a way that maintained the circle.
I use rubber bands to hold them to rubble. I put rubber band in the middle it will cut through the frag, thus making two frags later i cut cut the plug in half and glue the two halfs to something bigger. I like larger peices of rubble for toadstool or 3 inch tile plates to support them as they grow out. I cut the frags evenly roughly the size of frag plug in width easier to split the difference with rubber band.
Very easy to do overall. It was the first type of coral I ever fragged.
I also put the newly fragged ones in lower light causing them to strech up towards the light sooner instead of streaching out first. (Both normal light or low light works, just my method to get the stalk shooting up faster)