Is the technical term for what Robbie and Callum are doing and I think this is my first blip of them doing it. It's thought to strengthen social bonds - Robbie and Callum are litter mates and have always lived together in close proximity as they are house cats. Here, Robbie is grooming Callum, and that happens more than the other way round as Robbie is dominant - he's larger and heavier than Callum so can often get his own way e.g. shoving Callum away from the food dish that he is aiming for, precisely because Callum is eating from it. But in general they get on well together and I don't often have to intervene to keep the peace - and I love it when they allogroom!