Autocunnilingus refers to the act of a person with a vulva performing oral sex on themselves. It is classified as a form of masturbation. It is not an act most people - if anyone - can perform and there is no scientific literature that mentions it.
Autocunnilingus would require a high degree of flexibility, even compared to autofellatio because the penis extends some distance from the body, especially when erect. Alfred Kinsey did report on the behavior of autofellatio in "Sexual Behavior in the Human Male," and while he noted that "a considerable portion" of males attempt this, he estimated that only two or three out of every thousand would actually be able to manage it.
Although there is plenty of speculation and internet lore around autocunnilingus, most analyses of these images and videos have found them to fall short of what we might think of as cunnilingus, and certainly of what would be required for self pleasure.
