VBird - I was having the exact same problem as you. It's a matter of timing - hit the R1 button to draw right when the dots first appear - then you should be ablt to do it no problem. I, like you, was waiting till after he says "haha that tickles" etc to draw the dots on him, which is too late.

Hope that helps, can't wait to try the tough Oni island one everyone's talking about~