drink is what girls use as an exscuse to deny what they have done, of course sometimes, especially with the stiffer of drinks, it can actually mean she doesnt rember shit, all depends on how drunk she actually was.
another thing to remeber is that a guy goes to a club, it is to socialise but they are normally on the look for a k-close, a n-close maybe even a f-close, the only thing that tends to differ is how much effort they put in to attempting to obtain these closes. A woman can go months without sex because by going to a club, especially attractive women, they can get enough validation from being stared at, approached, grinded, groped and maybe even a cheeky fingering!
A guy could see this as escalation, but a woman can see this as increasing validation, once its reached a certain point of validation that she feels is enough, she can quite happily leave thinking 'i got mine', whereas its easy for the male to be left feeling they have lost out on an opportunity to claim more...
so basically what im saying is, one way of looking at it is that shes just might of used you...
