Yeah, it's a fairly... obscure term even for a native English speaker. I've really only seen it used in English translated doujins, but it's the only 'toy' called rotor I can think of. Though I don't commonly browse women's sexual relief devices, so it may be more common than I know of.A "rotor" might be a vibrator egg? Oh jeez.
In all honesty, I was actually thinking of the rotor of an airplane:
So either, I was given something simply weird, or I was misunderstanding something. Hence my wish to inspect this "rotor" further.
Well, let's see what Pops tells me.