Nevermind that, lets get back to the girls' conversation!
I do always nod though, never wave. Too leant over on sports bikes and u need to use both ur arms as support, otherwise u end up leaning on one hand which can cause u to begin a counter-steer move, etc. Only in the extreme of course, but it is too risky takin ur hands off on a sports bike (Except to stick ur finger up at some sod in a cage whos cut u up)