This is the first time that I have seen this sort of behavior. The video (animated .gif file, actually) is a bit peculiar and I hope it plays for you. Below the video is a still image in case the video disappears. If you click the object in the middle you get music and the object disappears. It just repeats so you’ll have to stop it! It is interesting cat behavior so worth showing and cute…..You have to have some cuteness on a cat website.
This kitten behavior could be the nose-touch-cat-greeting being done in an unconventional way! That is my impression.
The kittens look as if they are calicos — tortoiseshell and white coats. You can see the hint of orange fur. They appear to be random bred cats.