I also notice that Bella usually has her eyes closed when she washes herself. Her eyes are closed as she wets her paw and brings it down over her face, and as, she holds her tail between her paws and licks and sucks it. She looks so completely involved. Meditation on washing tail. I will image the same. It works for me.
Now, Bella licks Tiger, and, then, herself. She works with the same zeal. I wonder if there is any difference for her, when cleansing Tiger or herself. They are siblings, so, there is that. They sometimes seem as one, though their personalities, responses, and darings are very different. It just seems that when one of them perceives washing as needed, the cleanse and comfort begin.