The Domestic Cat: The Biology of its Behaviour,edited by Dennis C. Turner, Patrick Bateson.
Specifically, here, on rubbing.
Previous post has wrong URL. Doesn’t matter, book isn’t nearly hard-core enough.
But I did find this:
Responses of cats to petting by humans
Authors: Soennichsen, Susan;Chamove, Arnold S.
Source: Anthrozoos: A Multidisciplinary Journal of The Interactions of People & Animals, Volume 15,Number 3, 2002 , pp. 258-265(8)
Abstract:
There is evidence that different gland areas in animals of the cat family have different functions. This study showed that nine cats gave more positive and fewer negative responses to petting by their owners in the temporal region (between the eyes and ears), the reverse to petting in the caudal region (around the tail), with the perioral (chin and lips) and non-gland areas intermediate. This suggests that cats prefer being petted in certain body areas.
So now you know. Ars longa, vita brevis.
Be careful stroking a guinea pig under the chin. I had one that would snap at me if I did this (stroking back fur elicited rodent purrs).