"Hang on Sloopy" is about being in love/a relationship with a girl of another socio-economic class. Wes Farrell and Bert Russell wrote the song in the mid-1960s, and it was originally titled "My Girl Sloopy"; "Sloopy" is a reference to American jazz singer Dorothy Sloop, who often went by the name "Sloopy."
The first stanza speaks to the boy's love and concern for a poor girl, whose father holds some menial or socially undesirable job that she is ashamed of. He tells her he doesn't care what her daddy "do," and that he's in love with her and to hang on, things will improve.
The second stanza speaks to the strong sexual attraction between the two, and is a veiled reference to the act of fellatio, with the boy laying on his back. He delights in her long hair, and coaxes her to let her hair down and "hang down on me." Backed by the chorus, he urges her to "come on, come on." He tells her "it feels so good" and that she knows it feels so good. The song quickens in tempo and he exhorts her to "shake it, shake it, shake it," letting out a "yeah!" before the song crescendos with a long howl, symbolizing the ecstasy of his orgasm.