My stalker kitty is so bad that she finds hanging cords to do her butt when I'm not available. There's been alot of things mysteriously unplugged around here.
I've never heard it referred to as that!!...Reilly does it when you pet him there and so does my mom's cat Simmie (she is a female)..her tail also vibrates or shakes like a cobra's tail when you pet her!
Over the years, it would seem that about 75% of our bengals have done/do this sort of thing. The other 25% don't seem to react to it and will remain in whatever position they were in.
Also seems to be trans-gender in my case.