I sure you posted that for comic effect, but for a lil' mental exercise, let's consider it a bit seriously for a moment.
Terran felines, yes, have multiple pairs, but to paraphrase what Ptrope has repeatedly stated on the subject, just because Caitians may share some
physical attributes with earthbound cats doesn't mean they have all
those same features. Obviously, there are some differences. Housecats, or even lions for that matter, don't normally stand upon their hind legs (for any length of time), operate computer "switchboards", or talk. So why must we assume M'Ress has 3 or 4 pairs of mammary glands? Her ooficial model sheet (used as the basis for her pointing pose in "The Practical Joker") suggests she has a bustline comparable to that of human females, just a bit more subtle compared to the animated Uhura. True, that doesn't really prove anything. M'ress could be flat as an anorexic runway model and what we are seeing is merely her uniform being filled out by a thick and fluffy pectoral "tuft" of fur. In that case, she could
have multiple pairs, and they enlarge only when she has cubs. Really, it's anybody's call.
But multiple pairs are not really my thing (though I'm aware some people go for that and who am I to judge?), so in my mind, M'ress leans a bit more towards the human norm' in that regard.