Hmm, well to start with we're not quite sure how old she is. I've heard conflicting things from different people at the shelter, and anywhere between 8-12 seems likely, so I'm ball-parking it at around 10-11, but really I don't know. They first had her there in 2007, but there's some confusion as to how old she was back then.
She's very chatty, gets very over-excited several times a day, which I initially put down to her just wanting affection, being very sociable, but I've never known a cat quite like this before so I'm second-guessing myself now.
She drops her front end down and leaves her back end up in a very purposeful way, whenever I'm stroking her and giving her a fuss when she's up and about and miaowing. Different to how cats usually do when you scritch the base of their tail. I haven't noticed whether her tail goes to one side when she does it or not, I'll keep an eye out for that. She'll do this a lot when she's in a headbutting mood, so I get headbutts, she rubs her whole side along my head, and then I get the bum. During all of this, she lays down on her side a lot, flopping down, her bum still clearly out/up, and she'll roll over onto the other side, all very excitable like she can't settle, in a frantic kind of way, then up she comes again, more head rubs, and bum in the air, lots of mews, lots of purrs. Often, if she's in an excitable, lovable mood, and she goes to sit down (the kind of sitting down where all 4 paws get tucked in underneath and they look like a loaf of bread
- the position I call the kitteh loaf) everything gets tucked under at the front but that bum stays up in the air for a while. At first I thought she had something wrong with her legs! But after watching her for a couple of days she clearly can bend her back legs properly (although she really does flop down heavily when she lays down in her cat bed, as if her legs won't take her all the way down so she thinks "fuck it" and just throws herself down).
I've got a few windows open, but is that enough for males in the area to get a whiff? I presume it's not detectable to the human nose?
I'll take a look at some videos. If it tends to last for about a week once a month, I'll see how she is this time next week. Maybe she is just ridiculously affectionate.
Edit: I should add, there were other cats in and around her bit of the shelter, and none were showing any interest in her. Of course, I don't know whether they were male or female, so... They had tried to introduce her to other cats a few times during her stay, but she hated them. Presumably they wouldn't have done that if they weren't confident she'd been spayed? Unless they were all female, I can't remember.