"Yeah, but we are just hanging out, right?"
YOU DO NOT NEED TO SAY THIS!
I hate to burst your little bubble, but you do not need to say this to a female when hanging out in a friend type of environment or at the START of a very laid back relationship. JUST DON'T SAY IT!
I know you all think that you have it ALL figured out and that you run the world and everything, but I am here to tell you that we (chicks) have a pretty good view of what is going on in the world as well. Ok, well most of us do anyway. I am sure that the crazy ones wondering around may not see it the same as the rest of us, but you have to trust that there are more normal females (who are capable of rational thought) then nutters.
Again-point being is that you do not need to say this!!! TRUST me when I tell you that we are 'just hanging out' with you as well but we are smart enough to not say this to you!
*oh...and saying that to a girl is not going to get her to have sex with you...so don't even think it!