"Matthew" wrote:

Richard this quirk may be your fault some cats get over stimulated when
being petted this can come in the form of aggressive play, biting and
hissing.

I thought of that, but the result is the same, even if I don't touch
her. She gets up on my lap, I never lay a hand on her, and the results
are the same.

Anyway, I'm not so much interested in identifying why this one
particular cat is quirky, I'm asking the larger question of how much
to reveal about such quirks.