Sorry, I'm confused. There are 3 cats in the photos.
They will be BFF.Both female, I know females tend to be more territorial but I'm assuming that doesn't apply as much to siblings who are always together. So far they're best buds and play together, groom each other, sleep next to each other, etc.
I always used a squirt bottle. Teeny bit of water in their face will soon prevent this annoying behavior. Very soon just the sight of the bottle will deter them. Aluminum foil is also good - many cats hate it underfoot.Anyone have any tips for keeping kittens off the kitchen counter? They both learned to jump up there today lol