A phone is a poor hosting device in a conventional sense, because it's battery powered and keeping the connection up will drain the battery. If you want to P2P-host something via your phone, it should be a service that can somehow piggyback on the ephemeral network connection strategy that mobile devices are already using. The closest thing I've seen to that might be SecureScuttlebutt, but even then it's not ideal. IPFS hosting might also work, but again only on a highly ephemeral basis.