This is an almost grown up tabby kitten kneading what he or she thinks is his mum’s breast to bring on the milk to drink but he is doing it to the rump/stomach area of a male Van-type cat who might be his dad so it looks like a bit of unrequested, spontaneous kitten massage. The cat being massaged gets a bit tired of it quite quickly. So would you if you had a kitten kneading your stomach :). On reflection, the cat being massaged looks like a kitten himself. Perhaps he is related but that would seem unlikely as the coat types are very different.
That is my interpretation of this. Do you have a better explanation. I know. The kitten really is massaging the other cat. Wouldn’t that be nice?
I haven’t seen any evidence that suggests cats massage each other. They do groom each other and that is almost a form of massage. It is certainly therapeutic.
Note: Sometimes, videos get pulled off YouTube which leaves the embedded video blank.