You really shouldn't use ff because people who didn't do anything wrong might die and reds will start to kill each other. However before I had powers I would do it quite often but I would flash (toggle) it for half a second to kill someone. If an admin or donor is on then don't do it, ask someone with power to either start a vote or for the admin to do what they need to do. If no one is present to help you should really avoid using ff but if it's absolutely necessary and the person in question is purposefully being a troll then try and teamkill them in a fashion where no one else dies mistakenly. If anyone else does die it counts as a freekill and you should slay yourself.