What you're talking about is when a cat is "kneading" their paws. They did that when they were nursing kittens to get their mother's milk stimulated. It is said that they will carry on this trait when they are adults and when they "knead" it gives them a since of comfort. They "knead" when they are content and happy, just like they were when they were with their mum. So, be happy! Your baby thinks of you as his/her mom!
I never personally had a litter of kittens, so I'm not 100% sure, but I do believe they put their paws on their mother's stomache and knead while they are nursing the get the milk flowing better. Puppies do it too! When my dog had puppies, they kneaded Susie's belly. But when they got older, their claws got alot sharper and really scared up Susie's belly. We were told later by a vet you're supposed to clip and file their claws...oops...anyways, I'm not saying the kittens will scar your cat, because remember, these were 7 HUGE large breed puppies! Compared to a little (takes a shot in the wind) .5 ounce kitten, I don't think they'll do quite as much damage :wink: