[Larisochka]

The "mix" thing is what kittens and pups do on the mom's teats to help "let down" milk.This is all rather like thumb sucking in kids, but there is no peer pressure from other kids to stop

That's funny. I've never seen it in adults, but I've watched a lot of puppies and I think this is exactly what it is....it is that kneading motion puppies do (along with the suckling) to get the milk flowing...if you watch puppies, this kneading stops when the milk starts flowing