This is the first penetrative action, and, as such, is the responsibility of the one taking the action (the male). The difficulty of this situation is the very thing that the author says is irrelevant though, what actually happened to lead up to it. (The drunk factor is also important.)
“ We weren’t making out I don’t think, but maybe we were. I was blacked out at that point.” This is why it is so problematic to assign blame for drunken encounters. In point of fact, the woman is not responsible for the man poking his finger up her. To suggest that it is is victim blaming. But the discussion-worthy part of your post is the idea of making the decision to drink. Who should bear the blame for actions taken under the influence? Perhaps it should be the person who takes the action, as in drunken driving. Just because a person is intoxicated, he or she does not automatically forget what is lawful and what is not. It is the level of intent that varies: i.e., killing a person with a car while drunk might be negligent manslaughter, while purposefully running them down while sober would be 1st or 2nd degree murder.
I do not believe that the woman bears less responsibility for her actions during a blackout state (the very fact that she can’t recall them means her recounting of them is problematic, and the idea that she was making out with the guy is planted in your mind simply by her speculating after being UNABLE to remember what she actually did.) The man has not been heard from, so we don’t know if he remembers the finger-sticking part, but I contend that he is still responsible for it, if only at a reduced level due to his intoxication.