[Samantha Rogers]

Somewhere, maybe Salon, I read an article not long ago that may have some bearing here.
It concerned a young woman in New York who was extremely active sexually, and particularly experienced in certain kinds of extreme, limit testing S&M practices. At some point she got involved with a group that practiced Tantric sex. According to her, she had a very frightening experience in which she was engaged in a Tantric maneuver with another woman, and due to her breadth of experience in the other scene, she accidentally tripped into an area usually only attained by tantric masters after many years of preparation. It freaked her out completely. She entered into a wild convulsive, out of control orgasm that was anything but pleasant. Apparently it lasted many minutes, during which she actually thought she might be dying. It was almost like a seizure. Later, she was left in a state where she experienced sudden, out of nowhere orgasms that would grip her at totally unwanted and unpredictable moments. She stated that she has since had to swear off all sexual activity, trying to regain her life.
I doubt this is the same thing you went through, but the nervous system is an amazing and myterious thing. Perhaps the two things are related?