Flirting is being extra nice, in a way that clues the person that you are interested...its spending as much time with them as you can...<br />
and if the interest is MUTUAL he will flirt back immediately...and look for as many moments to be with you as he can...until after a while the couple grow close enough to want to exchange .... fluids. ;)
How long it last.
? Do I really need to answer that?? I am sure you know...