This happened to a friend of mine at a birthday party for someone else. He came to me the next day, seeking advice. He said he'd had some punch that he was sure had been
spiked, and had almost no recall of how he spent the last part of the evening.
Using a repetitive recall technique, I was able to help him slowly tap into what happened. It seems that he was quite inebriated when four guys carried him upstairs and threw him on a bed. A short while later, this girl came in and started tugging his clothes off. He was still quite smashed, so any concentrated motion was out of the question. He didn't really have the presence of mind to decide whether or not he wanted to do it, but, well, it happened. She, on the other hand, was far less intoxicated, if not completely sober.
Some people laugh at the idea of a woman raping a man because an erection is necessary. Don't let this idea mislead you - an erection can be caused by nothing more than physical contact. It is not always a mentally-precipitated phenomenon. It is also not true that alcohol prevents erection in all men; results vary from person to person.
So anyway, the girl proceeded to stimulate him to erection, and then she straddled him.
He was somewhat confused about the ordeal for several days after finding out what really happened. It turns out that he called the girl and talked to her, and confirmed that what he recalled was correct. He was especially terrified that she might have got herself preggers. (Catholic families on both sides, you understand.) I could see it in his eyes. He knew that he would be blamed, no matter what. Statutory rape and all that. She would have been able to stick it to him with ease.
Now, this fellow was a South American. In his culture, the idea of a woman raping a man is ludicrous. Such an idea was an ill fit for his mentality. The girl was also a South American, so she probably thought it was "what he wanted," like the girl from Hodgepodge's writeup, above. The idea of a woman raping a man would have been equally ludicrous to her. They were very close in age (17ish), so it was no huge surprise when I learned they were actually going out. It didn't last long, of course. When the hormones started subsiding, he realized that she was a pathological liar and a manipulator, and broke off the relationship.