It really sounds like they are interacting well so far. Hissing is ok, they need to teach each other their limits and that is how its done. I am happy to hear its going well. Maybe try to get his attention off her when she is in the litterbox.
So in November I got a cat, whom I love very much. The rescue named him "Sweet Tea", but I talk fast and say Sweetie, so when that wasn't going to work I named him Prince due to the fact that my nickname as a kid was King. I've got a studio apartment in which the only door is the bathroom door, he's got his castle...his tower...his stand, his hut, his tree...He's probably the most spoiled cat ever, but he is hyperactive. He's cuddly when he wants to be, let's me pet him when he wants, but is otherwise aloof. He's been with other cats when he was at the store, even played with them because they could move freely between floors.
Prince is now eight months old, and has been an only pet for approximately three to four months. He's an orange tabby and looks like he has Siamese in him. My vet and a few friends even believe he could be part siamese
Now comes the present night. I recently found this adorable all black cat at the pet store I work at. She is my dream cat, (I'm a dog person and prefer black cats if I ever had a cat, Prince of course charmed my heart). She's small for her age just like Nikita II, a cat I had years back that I unfortunately had to leave behind with my ex because my grandparents-whom I stayed with at the time-did not want animals around. I've named this cat Nikita the third, she is one year old and has been in foster care with multiple kittens. She is confident, and has no problems exploring the apartment. She's so sweet and lovable, a lap cat who is very cuddly (perhaps opposite of Prince, who is aloof and hyper)
Now here's the problem. I'm in the process of doing the site swapping introduction. I didn't think Prince would be territorial as he is, and the foster lady said it seems he might be jealous, which could be expected; but he's hissing whenever he gets near her. He hissed at the kennel, and I moved him close to the bathroom door where she's at and he hissed at the door.
I can hear her crying in the bathroom as Prince moves about the living room and bedroom freely (again, only door is the bathroom door. I have a litter pan, food and water in there for her right now).
I don't know how long I'm supposed to keep one cat in one room and one cat out before swapping them around. If it's an hour each, or god forbid 24 hours like someone else told me, and I don't really want them to be cooped up in that room. (Especially Prince, who I've put in timeout in there before), and I know Nikita hasn't hissed at him since she's been here-not even with the method of rubbing one cat with a sock and rubbing the other. She's perfectly fine. Prince, on the other hand, hisses even with the sock method-though not at me but at the sock.
After holding Nikita, he meows and doesn't want to be held against my shirt which has her scent. So I'm not sure if I let them in the same room together, if I even should. He hasn't yowled or anything, only hissed....but I don't want to leave them in that room, especially Nikita, who I just brought home! Like I said, I didn't expect Prince to have been here long enough to become territorial, but maybe I underestimated how long he's been an only pet for.
Any advice? Any tips? It's funny, this is my first time actually deciding to post anything here, though I've been scouring the site numerously over the last few months, haha. How do I even do this introduction thing? While she's in there, Prince sits at the intersection point of the hallway and bedroom, staring at the bathroom door.