Actually at my ITP, there was a girl with a deaf sister who cued. Only she and her immediate family used it, and they only did it when speaking with the daughter, not with each other (so essentially, she couldn't follow along with their conversations with each other, only conversations had directly with her).
From my understanding, it is around 8 different handshapes placed near the mouth that give a clue as to what phoneme is being used (like which vowel, the short a for example).
There is still an organization that supports cuing, but honestly I have only ever seen the two of them doing it (and now since both of them are learning ASL, the deaf woman and her sister, it's falling by the wayside). It seems pretty basic to learn, but there's essentially no demand for it.
