Thanks for that, I am starting to think about what you said, and I may or may not report him, but will make sure to stay away from him and people like him. I don't drink, so I can at least avoid those situations. I am relieved that I most likely will not get pregnant from this, as that would be terrible for me, being in college and all. I will make sure to avoid this kind of situation from now on. You have been a great help, and hopefully I will be able to get over this without any physical or emotional pain. I know that if I had stayed, he probably would have raped me, which is extremely scary for the 20 year old virgin me. I thought he was at least somewhat trustworthy, but now I know better. You have been great to help me out with this problem!
You don't have to report him, but a lot of people are confused about what constitutes consent or the lack thereof. Flirting does not give permission for any kind of sexual activity. Looking like, or even being a "skanky" college girl, even if you've had sex with 50 other people, does not give him permission to do anything with you. Giving permission for fingering or oral sex does not give permission for vaginal sex. And consenting to a massage does not mean you consented to being fingered. It was not a lapse in judgement on your part to expect to have your boundaries respected by a friend. Sadly, the majority of sexual assaults and rapes are committed by "friends" or acquaintances, not strangers. I would not get drunk anywhere near this guy, and I would watch anyone he goes to take home from a party to make sure they look willing and reasonably sober.
Again, you should do what you think is right and you're comfortable with, but don't blame yourself for what happened.
Thank you so much for your answer, that is a huge relief. However, I wouldn't feel right with reporting sexual assault because it was not that. I know him and I was flirting with him a little, definitely not trying to have sex with him, but he misunderstood and apologized when I told him I needed to go. He clearly thought I was just another skanky college girl probably, which I'm not, and he's a college guy, so it is to be understood. However, if he approaches me again, and even suggests anything, I'll tell him no and report assault if he tries anything. I had a momentary lapse of judgment when I let him give me that massage, and will never do that again. But thank you, once again!
You are so unlikely to become pregnant from that that it would probably qualify for a world record if you did manage it. Theoretically, if he had just masturbated and had sperm on his hands--maaaaaaaybe possible. I wouldn't worry about being pregnant from that.
However, if he suddenly forced himself on you like that (I get a strong impression that you did not want to be fingered or give him any indication that you wanted to), that's sexual assault. And by "indication" I mean enthusiastic verbal or non-verbal (like moaning and pushing into it and pulling your underwear down), not that you froze up for a while and didn't try to fight him or punch him. You should report him, even if you don't file charges, because guys who completely ignore consent and try things like he did usually keep doing it.