Congrats on your 2 kittens!!! Thanks for the update. I'm so glad that the kittens are now home with you. I've never had any of my male or female cats trying to suckle on each other before so I can't help you. He's probably doing it because it makes him feel more secure or like Laura said he may have been weaned too early. Hopefully he'll outgrow it. I wouldn't separate them unless it's hurting his sister.

I'm sure it'll take a while for your other cats to accept the two kittens. Just be sure to give the big cats plenty of attention. At least the kittens have each other to play with so they won't have to be jumping on the big cats. Good luck with everything and I can't wait to see some pictures of your two newest additions.