Help With Strange Cat Behavior/problem

I am completely perplexed as I've had many cats and do not know what is going on with two (2) 5-month old kittens I have, which are both female. 2 days ago I noticed a wet spot when I picked up one of the kittens but did not think much more about it until the kitten rubbed against my hand and left a wet spot on my hand. I smelled my hand and it smelled musky (if you know what I mean, without being graphic) and I thought that maybe the kitten was in heat. I had scheduled the surgery for getting them fixed already but wondered if she had gone into heat early. I was FINALLY able to identify where the wetness was coming from as I picked up the other female and she had a clear liquid (for lack of a better word) pooled around her lower lips. I touched it and it smelled the same as the other cat, so I watched for it on the other cat and just now finally was able to see this "pooling" of liquid on her bottom lip. I'm wondering if they have a cold ... if there is such a thing or what in the world it is, but I've just never seen anything like it and I'm very concerned.

Please help and thank you for your helpful comments.

I've never heard of that, it may be worth while to go to the vet, or at least call.

My guess is they are in a "guiet" heat. As I positively know many queens in heat are leaving a lot of fluid. (Im PA of two pedigree males, so we did had about 10 females for mating). And I know some females have a "quiet" heat, humans dont noticing (but male cats do, especially if fertile!).
5 months is young, but not at all impossible.

And why both at the same time? Humans, but also cats, living together and being pals have often their periods at the same time.

BUT. Dont do neutering surgery when they in heat - bigger risk for bleeding!
And IF you do because scheduled: tell the wet so he is prepared!

Do contact a vet if you wish - but ask him/her if it may be a heat...

When you take them to the vet, have their teeth checked. It's possible they are teething, or have some inflamation of the gums.

With lower lips, do you mean in the mouth or there behind where the tail is?