Oh, girl.. you got lesbian sex questions, you should just ask! Hahaha.
I find that even gay people have very different definitions on what constitutes ‘sex’. The last girl I slept with maintained that it wasn’t sex unless someone went down on her and she got off. My opinion is that if one of the parties has an orgasm, it’s sex. Anyway, definitions/opinions vary.
Scissoring.. well, I think the people who use this term aren’t entirely clear on what it means and often confuse it with frottage, which causes more confusion for everyone. While I have engaged in the act of scissoring (a term I hate, by the way), I hadn’t heard the term until maybe a couple of years ago. Make a V (or peace sign) with both hands and then put one V inside the other, fitting the two Vs together at the crotches of each, kind of like an X. The purpose is full-contact vajayjay rubbing. Honestly, though, as much attention as scissoring gets (people seem especially fixated on it), in my experience, it’s not that commonly practiced. It does feel really good and can be supremely hot with the right person, but it is a rather awkward position that’s hard to keep up for very long.
In the context of this story, I would guess that ‘lesbian sex acts’ would mean fingering, touching, and rubbing/frottage, seeing that she made cunnilingus a separate category. I was intrigued by this sex diary and read a bunch more; it would seem that in the final tally, each person includes oral sex as a separate category, so this is not just a lesbian sex thing or the diarist being odd.
I’m a bit confused by ‘riding’, as I usually associate this with female superior penetrative sex, and it didn’t sound like there were any toys involved. So my guess on this is that the riding involved finger penetration and/or on-top frottage.