I have a one year old, spayed female who absolutely loves to "mark" on the bed! She used to urinate on the bed to let me know that the litter box needed cleaning, I have since then switched to cleaning the litterbox daily and sometimes even twice a day, she has not urinated on the bed for a long time until this morning! I was washing the blankets and sheets and had put a temporary comforter on the bed since it's a water bed and I didn't want her popping holes in it. I come back from switching the loads to find a big wet spot on the comforter, sure enough she had urinated! The litterbox was spotless and no other cats had been in the room, she never does this in front of me so I never catch her in the act. She stays in the bedroom with me and one other cat Kitter, the door is always closed so that no other cats can come in, and when she's out and playing the door stays a crack open but no other cats are allowed in. Kitter mainly stays on the window sill and she's never had any problems with him. My opinion is that she's marking her territory, she is very territorial, and since it was a new blanket on the bed she wanted to mark it. I know it's not a UTI or anything like that because she urinated once on the bed and that was it, all day she has been using the litterbox as normal but the second I put a new blanket on the bed she decides to pee on it! Any ideas, thoughts, or ways to prevent this?! Thank you!