My strange kitty... (Q for cat folks out there)

[S.Taylor]

I have a pair of kitties, about 4-6 months old. One of them sucks his tail. I had noticed him some time ago walking around all the time with the last inch or two of his tail all wet. The kids told me why, but I just sat and watched him do it for the first time. He laid down, and groped around for his tail for a moment, them started kneading his pillow rapidly, and rooting as if he were nursing. Then he started making really loud sucking noises. He's nursing on his own tail!
Anyone ever come across this behavior in a cat?