There isn't a way to keep Jewel from doing this, and she's not doing something wrong. She's just being playful. :) It's not a dominant thing and as far as the pecking order goes, they'll sort that out on their own. The best thing to do with two cats is to keep them separated until they get used to smelling each other. Even if they've already been introduced, you can go back and start doing this. Having battles under the door is completely normal too and it's not something you should discourage. I'd keep the new kitty in a bed room for a few weeks and once or twice a day, put Lucy in the bedroom and let Jewel out for a few hours. This will let Jewel explore without bothering or being bothered by Lucy and Lucy can sniff around the bedroom. If they have a particular bed or blanket they each sleep on, every few days switch them. Again this helps them get used to each other scents.
After a few weeks have gone by, do some slow, limited introductions. Having tasty food to distract them with or a toy they can play with together (like a feather on a stick deal or a laser pointer) that way they are near each other but not focusing on each other. Then after some time socializing send the kitten back to the bedroom.
There is going to be a lot of sorting out the pecking order and playing going on when they finally do meet. Just to forewarn you, Cats playing looks an awful lot like cats fighting. There is chasing, growling, hissing, batting at each other, tackling and other antics. My cats do this at least once a day and it sounds like WWIII has broken out then after an hour they pass out in a pile licking each other. It's important to not interrupt them while they are doing this unless you see blood and fur flying. This is how cats play and get to know each other.
It can be distressing at first but you have to let them go through the motions otherwise it's just going to take longer because it has to be done. It's how they learn each others boundaries. If one growls or hisses at the other they aren't being mean or malicious, try to let them be. It's cat speak. What you are looking for is if they are wrestling around and Jewel or Lucy has the other pinned, is that if the cat on the bottom makes a high pitched meow or squeal that the other cat stops biting or doing whatever it is she's doing. That high pitched meow is the cat version of crying 'Uncle' or yeilding. If the other cat doesn't stop and you need to intervene, the best way to do so is to have a can and fill it with pennies and shake it loudly. This will send them flying in opposite directions from each other. It keeps your hands safe from getting in the middle of it AND since it's an outside sound so they don't associate bad sounds or 'bad things' with the other cat. It's the safest way to separate kitties.
Some cats get along right away, sometimes it can take cats months to start to tolerate each other. It just takes time so be patient. By going slow and keeping them separated it will go a lot more smoothly because by the time they meet face to face, they aren't as anxious around each other since they are used to smells and the others presence (even if they aren't face to face). Another good thing to do is to feed them on opposite sides of the door from each other. It stimulates a bit of bonding and they don't feel the need to guard food/territory. In time, they'll both mellow out.
The two posts above me are wrong. Cats are very social animals and the best thing for a cat is often another cat. I'm a vet tech and have worked in shelters, rescues and have fostered for years and know for a fact that 'for every one that does, there are three that don't' is false. We frequently encourage people who are adopting to adopt two kitties if they can because they do best with another cat in the picture. I mean, think about it, how many people do you know that have more than one cat? Do all those cats hate each other? Siamese cats aren't an exception to this, where they get 'territorial' is with people. They often bond to only one or two people and are exceptionally loyal to them. One of my cats is Siamese and best buddies with our other three cats, even though she was the first one in the house. Same thing with the Siamese I grew up with.
Good luck and try to relax. I'm sure eventually they'll be best buddies. Just give them their space and let them get to know each other, especially during those moments that might seem disconcerting. :)
This thread has a TON of great information from vets, rescue workers and pet owners for getting a new kitten and introducing it to an already existing cat, I highly recommend reading it:
· 9 years ago