Allowing users to navigate seamlessly between their personal devices while protecting their privacy remains today an ongoing challenge. Existing solutions rely on peer-to-peer designs, and blindly flood the network with session messages. It is particularly hard to come up with proposals that are both cost-efficient and dependable while relying on poorly connected mobile appliances. We propose CASCADE, a distributed protocol to share applicative sessions among one's devices. Our proactive session handoff algorithm takes inspiration from the BitTorrent P2P file sharing protocol, but adapts it to the specific characteristics of our problem. It eschews in particular trackers, and limits the seeders of each session to the devices most likely to be used next, as computed by a decentralized aggregation protocol. A key aspect of our approach is to trade off network costs for reliability, while providing a faster session handoff than centralized solutions in the vast majority of the cases.