I tap the same way Saidin does (green with no fretting hand, rest with fretting hand). The easiest way to learn how to play that way: rubber band trick (put a rubber band on the green note) this way you can have your other hand worrying about strumming if you miss until you get used to the fretting then you should be able to FC it. It's the only thing in the game I tap pretty much, I do everything else one handed and I've FCed the intro to TTFAF one handed before :D