Uni is a girl and she's spayed and she humps. She's done it since she was about a year old. She only humps her beds. But she's had many beds throughout her lifetime so far, and every single one she will hump. it's like she has to break them in for something.
she doesn't hump anything else, and doesn't hump people. She did hump her dragon toy once, but I think she's over him. I don't mind it and I think it's quite funny, so I don't stop her, but some people don't like it. You can train them to stop if you are persistent.