Doing things like swirling the fermenter fosters an attitude of wanting to screw with your beer. One minute you'll be swirling your beer (haha, look at me!), and then before you know it you will have dropped a chuck key into the brew(f*****k). True story, not mine. The moral is to leave the beer alone. Swirling does nothing but potentially mix nasty tasting krausen scum back into the brew.