Cat-human communication is a bit different from cat-cat communication,
and while I mostly rely on the former I do intentionally include a few
bits of the latter (I'm not as fluent in cat-cat as I am in cat-human,
but like many (most?) cat owners, I've picked up a few useful phrases).
Sometimes a cat, when faced with a human attempting to speak the cat's
language, will look confused, as though thinking, "I know what it means
when a cat does that, but what does it mean when a human does it? Is
this human okay?" Other cats simply react as though to another cat,
without being troubled by seeing the wrong species giving the signals.
One of the cat-things I do is the friendly "let's smell each other's
breath" approach. I'm not sure exactly what it means to
cats, but it does seem to reassure them (and can help to convince an
unfamiliar cat that I'm friendly, if I'm allowed to get my face that
close in the first place). This is, of course, done in the cat "I want
to analyze this smell" fashion, with the lips slightly apart and very
gentle, shallow, short breaths. (This is apparently related to "flehming", and aids delivery
of the inhaled sample to the vomeronasal organ. I was about to add
that although I thought this was a special feline organ, I did notice
that I get different information when smelling things in this way --
but I paused to google it, and discovered that the vomeronasal organ
(or Jacobson's organ) is present in several species, including humams,
though it's apparently not connected to the nervous system in adult
humans (I wonder how much of the change in food preferences between
infancy and adulthood are explained by the shrinking and disconnection
of this organ). Wikipedia says that "some researchers argue" that it's
functional in some adult humans; this might explain my acting like
a "supertaster" in some regards and not in others, or may be completely
unrelated to how I perceive taste and why breathing with my lips parted
and my tongue positioned to direct air across the roof of my mouth
sometimes gives me more information than smelling things in other
ways -- it could simply be the pattern of airflow across my tongue
that matters, rather than flow to the spot where my vomeronasal
organ may or may not still be, that matters. Ah, but I digress...)
Anyhow, one approaches the cat slowly and smoothly, head way
forward, lips parted as though one's sense of smell/taste works
the same as a cat's, and there's a good chance the cat will react
in kind. If you're not sure how to perform this maneuver from my
description, just watch two cats sniff each other's breath, or
pay attention to how your cat does it to you -- even if you never
initiate this, most cats will occasionally try to sniff your
breath in this way if they're comfortable with you (and all the
more so if you've just eaten something yummy, though very litle
of what I eat is yummy to cats). Some cats do it more often than
others.
But here's the thing: I suck a lot of cough drops, often
containing menthol, to deal with airway irritation not quite
severe enough that I want to use my albuterol inhaler but too
annoying to ignore (especially when I'm trying to get to sleep,
or on high-pollen-count days). I do not initiate the mutual
breath smelling thing when I'm sucking on a cough drop, or have
just done so, but sometimes Perrine chooses such a moment to
initiate it.
And then she flinches back, eyes narrowed and ears back, as if
to say, "Yeowch! What did you just do to my smeller?"
Apparently, menthol-breath is worse, from a cat's perspective,
than the smell of hot coffee (which in turn is much worse than
coffee-breath), but not as bad as the smell of a tissue soaked
in rubbing alcohol.
(So, uh, yeah, the whole point of this long entry
was the image of a cat trying to be friendly and getting a
snoot full of menthol, and looking startled and confused by it.
But I'm curious about other folks' sense of smell and how
involving different parts of the mouth affects the amount or
quality of information extracted from the air being sampled.
And, of course, always welcome feline communication insights,
and certainly don't mind providing yet another excuse for friends
to post random cute cat anecdotes.)