Autoing Without Cursor On Minion/Monster/Champions?

Ok so i see pros do these all the time like imaqtpie he autos a minion once but after that, he doesnt click the minion or champion again nor does he hover over them but he constantly side steps and the character he plays is still autoing a minion... How do you do that? Where like you can auto once they it locks on till it dies then to another WITHOUT any indicator or hovering over mouse. I would like to learn how to do that so i dont get like closer to an enemy by accident and can continue side stepping