Kittens knead at their mother’s belly when they feed, this helps to stimulate her milk flow.
When a kitten or cat kneads, they will push rhythmically in and out with alternating paws (kneading is also referred to as making biscuits or milk treading for this very reason). They often appear to be in a trance-like state, with eyes closed, sometimes drooling and purring. They really seem to be enjoying the moment and I definitely view kneading as a sign of a contented cat.
In many cats, this kneading behaviour continues into adulthood. Cats can often be found kneading a soft or furry blanket and some will even knead on humans. I have a cat who will also lie on his side and knead into thin air.
So why do adult cats knead?
One theory is that adult cats knead if they left their mother too early.
Another theory is that kneading is a throwback to the wild days when a cat would knead down the soft grass before making a bed to sleep, to squash down grass and check the ground for predators such as snakes.
Cats transfer their own scent from scent glands on their paws when they knead.
Entire female cats (queens) often knead immediately before they go into heat.
We will never be 100% sure of the reason cats knead but whatever the reason, they do seem to enjoy it and it doesn’t cause any harm. If your cat likes to knead you, take it as a compliment, he likes you a lot. There is no reason to stop it unless they are using you as a human pin cushion. In which case, you may either choose to avoid this happening, place a blanket between you and your cat’s paws or keep the claws regularly trimmed.