The recent success of online social networks hints at the general interest in socio-aware, user-centric networking applications. At the same time, mobile consumer devices are becoming both more powerful and more widespread. As an implication of these trends, user-centric networking can be realized directly between the users' devices, i.e. without depending on a server-based infrastructure. In this paper, we propose a novel hybrid overlay to facilitate the direct communication between user devices and enable the deployment of complex user-centric applications in a fully decentralized manner. In contrast to traditional overlay designs, our approach leverages social context to achieve a high interconnection between the devices of befriended users. Our overlay ensures the locality of user traffic and supports the delivery of messages to devices that are unavailable at the time of sending. Simulation results show that our approach achieves close to optimal latencies and is scalable in terms of network size.