There was a blog post linked a while back on this thread, about how women/girls are conditioned in society. I found it really interesting, because it is true. I have never found an acceptable way of "dealing" with unwanted advances on a night out- apart from "I have a boyfriend, he's that guy there, he won't like it if you grab my arse/make sexual advances/touch me without my consent".
I find it really difficult to say no to men, even over a medium like text when they are asking for something I'm not willing to give, especially if I've given it to them before. I don't think men understand how hard it is when you've said no for the second or third time, or given a fairly polite no, which can be just about read as a maybe, so they persist.
The one time I got physical with a man (he started grinding against me with an errection in a night club with litterally no introduction and I slapped him to get him to back off) he punched me in the face. The bouncers were uninterested and fortunately after that he left me alone. I am 5'4'' and weight less than 9 stone, the majority of men (the majority of people!) are going to be physically stronger than me, so I don't like getting into situations where things might get physical.
The other thing that annoys me is the assumption that flirting/talking = consent. I have never left a club with a stranger, I very much doubt I ever will. I'm happy, sometimes, to add guys on facebook/give them my number. That's not equal to consent. Neither is going on a date or agreeing to meet up, and I hate how some men view it that way.
Interestingly, I have been in a situation where the roles were slightly reversed- a much less sexually experienced guy (although older), less into me than I was into him, and I tried to be very careful with regards to sex, and only had it if he instigated it and seemed to be giving "enthusiastic consent". I know, obviously, someone has to instigate but I wish some of my male partners had given it some consideration.
With regards to reporting, I have never experienced anything worth reporting, but a friend was sexually assulted (as in sexual act performed on her whilst unconcious then she woke up) by a boyfriend, neither the police, nor the university they both attended were interested!