Kitten attempting to nurse on male cat.

I recently brought home a kitten and, lately, he has been trying to 'nurse' on my full-grown male cat. Vandyke (the kitten) is old enough to eat regular food and has been eating kitten chow for a few weeks. Do I discourage this strange 'nursing' behavior and, if so, how do I stop it?

Any help / advice would be very welcome. 

How is the full grown male reacting?  If he doesn't mind I wouldn't worry too much.  If he does he'll let the kitten know.  It could just be bonding.  How old is the kitten?

Vandyke is about 2 months old, maybe 2 1/2. My full-grown male cat, Muttonchop, doesn't seem to mind overly much. He'll put up with it for awhile and then get up and go somewhere else. It seems to me, though, that Vandyke is starting to do this every time the two of them snuggle together. I guess I am worried that it will alienate Muttonchop. He had a pretty hard time adjusting to Vandyke's presence.

I think it's ok. Maybe he'll stop as he gets older.  Vandyke is only 8 - 10 weeks old and is probably missing his mom and that calming nursing feeling.  Is he kneeding when he sits with you?

Okay, this may sound strange but it seems as if your kitten may not have been fully weaned or was weaned early. You did need to be careful that the kitten does not start trying to nurse on the male's private area. That will be bad for the male and also the kitten. You may need to keep them separate until the kitten no longer wants to do that. I've had trouble with it occurring in orphan kittens, especially young ones. You might try giving your kitten a soft toy that he could have instead to snuggle and chew on.

Vandyke likes to sleep on my chest and occasionally tries to burrow into my neck (also like he is nursing), but he doesn't knead me. I can tell he is comforted by my presence, though. I wonder if this behavior is akin to thumb-sucking in infants. More for comfort and reassurance than an overwhelming need to feed.

I don't think Vandyke was weaned too early. I adopted him from my mother-in-law and all the kittens were healthy and mom was still around to give suck if they got the urge. They'd been eating regular kitten chow at the farm for awhile, though. My mother-in-law didn't mention that they were still nursing regularly.

I'll keep an eye on the two of them to make sure Vandyke doesn't start trying to nurse Muttonchop's privates, but I haven't seen any evidence of that. Muttonchop was a rescue kitty and is a little strange, to be honest, and I just don't want him to develop any problems due to the kitten's behavior. 

I love both of my kitties and want them to be happy.