So Angel is m eldest of all three of my girls. She's also the most shy. She's taking her time adjusting to me, but we went from trying to bite me all the time, to at least giving me a 50/50 shot, so that's good. When I do tent time she often prefers to be left to sleep in her pouch. Sometimes she'll watch from the pouch, or pick a spot to perch and watch from there.
With all that being said, she has gone into her first heat. Not HER first heat, but her first heat that I'm experiencing, and the first heat that I've experienced with all my girls. I thought at first that she was just extra crabby today, because she was noisier than usual during tent time, and in general when handling her. Later on I was trying to catch a couple hours of sleep in their room before going into work, but they were noisier than usual. I got up to check, thinking they were just hungry because it was around dinner time. Upon further observation Peaches and Peanut were mounting Angel . There was definitely some humping motion coming out of Peaches. I immediately checked all three, more as a formality than anything, but they are all girls, and Angel's area is swollen as a female's in heat would be.
Dogs are not gliders, and I'm not trying to make the comparison, but animals are animals. Sometimes female dogs will hump other female dogs, usually for dominance. However, I have no doubt that, in animals, girls can sense when other girls are in heat. I also have no doubt that that can probably make them smell things, and maybe even wanna hump things. Is this unheard of, and should I worry? Or is this something that sometimes they just do?

I've never noticed the swelling that you mention when my girls are in heat...not to say that it isn't normal.

But, yes...animals are animals and they'll do that regardless of sex, nationality or creed. Mostly my girls just wrestle around with each other, not overly aggressively or with biting, etc. I've not observed them humping each other but, my male who was neutered before maturity will give it a try.

There's lots of noise making, spooning with tails all over the place, wrestling around, and I only saw the mounting thing once. I can't help but find it all very funny. I'm confident in my assessment that they're all ladies. If I'm wrong it won't take me very long to find out, but I doubt that I am, and I don't want to needlessly worry. I'm sure they're just trying to help a sister out