You're right..being asexual has to do with sexual attraction, not libido.
In fact, many asexuals have an unusually high libido..it's just not connected to any gender or person in particular.
In my case, porn does nothing for me, except for gay porn, which I only see as "romantic," being partially transmale and married to an "apparent" male before (he has since come out as non-binary female).
But other asexuals find pleasure in porn.
My theory is that mixed gender people have had their prenatal brains initialized with both male and female hormones (studies show that most male traits stay on the right hemisphere, female on the left), so opposite sexual attractions can cancel each other. For instance, I'll start to have feelings of sexual attraction for a female, quickly followed by revulsion, so I'm guessing my female side shuts it down. If I were to start taking T, my female side would be overwhelmed, most likely leading to sexual attraction only to women.
When I self-stimulate, I think only in vague gender terms, and can have orgasms from the perspective of either male or female or both at the same time. Strangely, when imagining myself as male, I have quick, explosive, almost violent male-type orgasms, and when I see myself as female, the orgasm is long, slow, builds, then continues for half a minute or more.
But when I imagine myself two people at the same time, male and female, I experience both orgasms at the same time, which can be almost overwhelming.
But strangely, I don't seek this experience, being very "meh" about self-stimulation.
