Without infrastructural support from base stations, mobile nodes in an ad hoc network communicate with each other in a peer-to-peer fashion. This poses a challenge in data dissemination among the mobile peers, each having limited transmission range and unpredictable mobility. In this paper, we first propose a novel mobility model to characterize user mobility in a civilian environment, such as a college campus. We then propose the application of Tornado coding as an efficient solution to the challenge of ad hoc peer-to-peer data dissemination. A mobile node is able to download coded file segments from different peers - at different times and in different locations. When it receives sufficient segments, it will be able to reconstruct the original file. Although Tornado coding itself is not new, we for the first time propose its application to mobile ad hoc data dissemination. Furthermore, we show how Tornado coding parameters affect the performance of peer-to-peer data dissemination.