Ok…I’m serious about this you guys!
Whenever she’s around a towel or blanket she, you know, humps it. She doesn’t do it to peoples legs, really just towels and blankets.
She’s a cockapoo, definitely female, about 10 mos. old. She was spayed a few mos. ago.
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Well, when I was a kid, my family had an (unspayed) poodle bitch that humped everything in sight all the time, including peoples’ legs. We never knew what caused it. I’m going to assume that it just feels good, and unfortunately you can’t shame a dog into decorous behaviour, unlike preschooler children. 
Honestly, maybe it just feels good to her? You could have her hormone levels checked if you want to spend the money, but I’m not sure what a vet could do for her anyway, esp. since her ovaries have already been taken out.
My grandpa claimed his bitch would hum The Battle Hymn of the Republic, but only when nobody else was around.
:dubious:
This question has come up a few times in the past year. I think even once in the last couple weeks…
Basically it’s just a dominance thing. Dogs will hump other dogs to let them know who’s in charge. Females will hump females and males will hump males, too.
My Golden Retriever was spayed right at 7 or 8 months, before ever going into heat and she humped these large stuffed tigers I had for a year until I gave up and threw them away. She was still humping one of her bed pillows last summer until I tied it to her cage.
Answer is …they just do. It’s not uncommon, just uncomfortable 
Indeed it has.
The answer to controlling (or “extinguishing” - that’s what psychologists call it) this behavior is in training, just as it is for almost any other annoying behavior that doesn’t have its roots in some kind of physical illness. And I just posted a resp here that will give you the best advice I know.
Once you have the dog trained to some basic obedience commands, when the dog starts “humping”, give it a command. When it obeys the command, praise it lavishly, even extravagantly. IOW, make a great big fuss about what a wonderfully good dog s/he is. Since your dog enjoys praise and attention more than nearly anything else (or there’s more wrong with the dog than one annoying behavior), she will very quickly learn that you don’t want her “humping”. Of course, you’ll hafta keep practicing obedience commands, but once you’ve got a dog with such lovely manners, that isn’t very hard. 