What is 'Yokoso boku desu'?

This is the 4th music and animation series titled “Yokoso boku desu” (Welcome it’s me). This series consists of three songs. “Let’s Coritsu”(Be isolated), a song wising for an isolated situation to be connected, “Yoko is Naive”, a song by a mysteriyous woman who has been waiting for something for a long time, and “Kosokoso Bokudesu”, where an earthworm boy, a senior guy, and others extend their own necks. Through these three songs, what do you see in Yokoso Bokudesu?