All our cats have kneaded on us. Grizz would circle the bed, and start kneading by our feet. Buffy kneads by my stomach, nose pressed against the blanket (hiding the fact that she's drooling on it), and then she plops over and falls asleep.
Willow, on the other hand... She "rides" my leg, in the sense that each leg is on teh other side. The right hind leg is on one side, the left hind leg is on the other. The right foreleg is on one side, the left foreleg on the other. Then she grabs onto the blanket by my ankle and starts kneading with her forelegs. She used to knead with her back legs, which felt odd. Now, she uses both. Well, she kneads with the forelegs and occationally lifts a backleg as if to make sure it's still working, make sure the leg behind her is still satisfactory. None of the other cats have ever scratched me with their nails, and Willow doesn't either at first. But then her nails start to make their way through the fabric and soon they come into contact with my foot. I don't mind it, since they're still moving gently, scratching any itchy spots. But then her nails start to poke me enough that my foot start jerking involuntarily. Then I try to shift my foot everytime she lifts her leg. I don't complain, she doesn't complain.
She then used to go over to her bowl of water that I had out for her, and she'd drink for like 10 minutes, or until the bowl was empty. Then she'd come back over and lie down. Makes me thing that holding onto the blanket with her mouth dried it up and she needed to "moisturize" it again, lol!