casual sex?

i woke up early and watched kristv, and kris made her  comment on the movie "secret affair"  she said "therno such  a thing as "casual sex" 

seriously what is the meaning of casual sex? for us? is this the same as "one time thing" or "one night stand"  

sure thing we all try that thing, in our owned mature way of doing it. but i reaally wanted to know, for us gir

ls  is all those thing are the same? or same way as guy think? its different, ofcourse when men cheats, girls forgive a little but never forget. 
but how do they classify a secret afair? or a one night stand? 

i know its complicate, a bit crazy f you think ofit , no woman wanted to call a misstrses or no gurls wanted to have a secret affair, i mean we all used our brain, we know the right thing, yeah but sometimes  your just trapped or attached to that thing, that you cant say no, or even stop, 


so think of it, casual sex is really different from being a mistrss or to a secret affair, really boys are good  on a casual sex, no string attached  no commitment just plain sex when their bored and feel like doing it.


its confusing because boys and girls have different mind and opinion about it. and also can you compare casual sex to casual wear? plain a simple?