I have an almost 2 year old spayed female feline, sole pet. For the first year of her life she was litter box trained, never had issues urinating or defecating anywhere else. This past year I successfully trained her to use a human toilet. During the training, she never had an issue/accident. The only two interesting, but probably unrelated things to note about this. She only uses the toilet she was trained on, there are two in the apartment. We think she used the other once, but are unsure. Second, she "announces" herself before defecating by meowing loudly for ~3min before the act. After she's done, she goes on with her day.
Recently, she has taken great interest in a
[cheap memory foam filled futon]. This futon is by no means new to her. She has co-existed with it for 9 months. Two weeks ago I caught her frequently sniffing and scratching on top of it. I'd just shoo her away. This past week though she had urinated on it twice.
My going theory is that someone had sat on it with "something smelly" on it and she felt like urinating on it...? Though this futon is very rarely used, maybe two people have sat on it in the past 2 months. And if so, the only "smelly thing" that I could imagine would illicit such a response from her is cat or dog urine. Which I would imagine someone would know about before sitting on a futon.
What could be the cause of this? Apart from what Google may tell me, is there anything that I may be able to do to stop future urination?