The herp store showed me how to do it, you basically take them by the tail and flick them overhand so to speak onto a countertop, its pretty instant and you are left with a mouse thats just kinda twitching, no totally limp. The girl there said that its just a reflex action and that the mouse isn't actually suffering. She said you do have to give it some muscle, or else, in your sympathy, will not give the mouse a quick death. I can't stop picturing the photo of that ball python above, thats so sad.