One night I was sitting at the computer when I heard a strange popping noise as of the bursting of many small bubbles in sequence. I looked around, but could not discover where it was coming from. When it stopped, I went back to the computer. Then it happened again. After a few iterations of this I finally pinpointed the source of the weird noise: it was Attica, whom I had recently acquired, and who was sleeping on the sofa with her paws in the air. Cautiously I approached until I was close enough to discern why my cat was popping: her tongue was moving as she slept, repeatedly forming and breaking a vacuum seal against the roof of her mouth.
That was the first time I witnessed Attica dream-nursing, as she was to do often for the rest of her life. When she was awake she would try to get milk out of me, out of my clothing, and out of the blankets on my bed, by kneading with her front paws and rooting around with her muzzle, all the time wearing a look of intense concentration. (For kneading she preferred my gut, but she was not particular, and would attempt to extract milk from my arm or my eye or my cheekbone if it was closer to her paws.) When she was asleep her lips twitched and her tongue flicked in and out as she dreamed, I hope, milky dreams. I never heard her pop again, though.