in brave new world is pneumatic the word used to describe a woman who has a nice figure?

This is true. Pneumatic is often used in the novel. Sometimes it is used to describe something with compressed air like the chair in Mond's office. It is also used to describe what it might be like to have sex with someone. In particular both Henry Foster and Benito Hoover describe what Lenina is like to have sex with. They refer to parts of her body and its desirability during sex in this way.