While recent work examines parents and children reading together on tablet computers, the ways in which interactive elements within e-books affect parent-child interaction are not well understood. We examine haptic feedback as a new form of e-book interactivity and analyze how parents and children exploit this dimension when reading together. Results from a laboratory study with 18 parent-child dyads (N=36) reveal that participants reading a haptic e-book talked more about the technology compared to those reading a regular e-book, and this additional talk was a way in which parents elaborated the story narrative. Parents reading a nonhaptic e-book, however, engaged in higher rates of expressive behavior (e.g., making sounds, gestures). This suggests that haptic interactivity provides a new resource for parents to draw out the story narrative but may also result in less parent expressivity when reading, both of which have implications for child comprehension and literacy.