Kaia Gerber fired up her Instagram this Sunday to post a smoldering bikini snap of herself in the pool reading Play It As It Lays by Joan Didion.The 18-year-old daughter of Cindy Crawford dislocated her wrist this week and could be seen wearing her long blue cast.She revealed in her caption that when she does an Instagram livestream about Play It As It Lays next week she will be joined by fellow model Emily Ratajkowski. 'Couldn't put it down':Kaia Gerber fired up her Instagram this Sunday to post a smoldering bikini snap of herself in the pool reading Play It As It Lays by Joan DidionHer Instagram album showed Joan posing against her yellow Cadillac Stingray in a 1970 picture Julian Wasser took for Time magazine.That photograph was taken.