My adult cats still want to nurse.

This origionally started when i got my 2nd Cat Pookie a male. I already had a full grown male cat when i got pookie, his name is casper. When i first got Pookie him and casper hit it off right away, they never had that akward stage where they hid from eachother. Almost right away pookie started trying to nurse off of casper. Casper let him do so and Pookie would just lay there and suck on caspers chest, stomach and sometimes armpit. I thought it was really funny at first and just thought he missed his mommy. But pookie is a full grown cat now, he's almost a year old, and every now and then i still catch him sucking on Casper. Casper just lays there, he occasionally kicks pookie in the head, but that doesn't stop him. Now I've added a 3rd cat to the family her name is Molly, she is about 4-5 months old, and i find that she's picking up pookies bad habbits. I walked in the living room yesterday and Pookie and Molly were laying side by side nursing on casper. Who like i said is a male cat. I pull them away and they still just go right back. Picture it, Pookie is much larger than casper and is doing this. If you want to see my cats to get a better idea go to www.wearesiamese.homestead.com/sunnygirl37.html. Please help me figure out why my cats are doing this and what i can do to stop it.

The cats are doing it because they were probably weaned too early. It is very natural for them to seek the comfort of nursing on mom. Cats who are weaned too early will sometimes do this through adulthood. There really is no way to stop them unless the one being nursed on has had enough and wont let them. The only other thing to try is the bitter apple spray on where they are sucking. The drawback to that is when the one cat goes to groom, he will get a good taste of it and it may prevent him from grooming properly.