My friend taught me about this about a week ago and I was surprised to learn that many other people didn't know... S makes you stop all actions until you enter a command again. I always complained about auto attacking and how it made my last hits so hard... or annoyed my adc when I was support. /noob
http://img.photobucket.com/albums/v139/lain8/ohitislove.png Oh, it is love.
Only time I ever use S is when playing Teemo and want his passive to kick in.
Otherwise, it's best to hold the right mouse button and move around - clicking on a minion when their health is low for the last-hit. That way, you have a much better shot at dodging incoming skillshots.
Last game, I laned with an Amumu who would just sit there (assuming he pressed S) when not attacking. Needless to say, he ate plenty of Nidalee Spears. If he were actually moving around instead, he could've easily dodged.
Best thing in life: Sex Second best thing in life: Pizza
From Serial Experiments Lain back in the day Fun fact: That is the one anime I actually liked, if only because it's essentially a P. K. Dick novel. edit: Of course, I have no idea what I'd make out of it now like eight years later.