It means waiting for something that isn't going to happen.
Its waiting for you to adopt it :D
He's waiting for you to say something/do something!
Because time seems more relevant when your waiting at the source for something to happen
Waiting for Godot
The girl may say you are cute and no longer talks because she is waiting on you to speak first.
Maybe he is waiting for you to make the first move. It could be that so that he will know if your are interested in him too if you do make the move.
You should never have unprotected sex. I am also unsure as to what you mean in saying "how long". Exactly what is it that you are waiting on?
It means don't wait for later to do something. Use your time more efficiently
I am waiting
waiting or expecting
sentence is like a riddle... answer is waiting
I've been waiting for you