Agreed. I'd think it'd have to do more with the orgasm, but I might be just wrong.I think pleasurabe moments are captured permently in your memory. Sex and good Sex will be something you can easily remember.
I can remember sexual things that I did years ago, that did not even envolve a partner.
I remember seeing up my friends aunts skirt when I was 12 in vivid detail.
The smell of this girls perfume in High School, that I liked.
Walking in on my friends sister nude by accident.
Some memories stick with you for a long time.
Of the experiences listed were any simply "firsts"? The sister thing was "taboo" socially, and I don't know whether you have a disposition to olifactory senses or not. Regardless do you physically react, without stimulation otherwise, to these memories?