Here the bands plays with the meaning of ‘back door’, the first obvious meaning, that follows ‘check for me, girls’, that can be read as 70’s ‘twerk that ass for me, ho’, hints at the possibility of anal sex between the two. The second is a reference to the “Back door man” in blues imagery, who is someone having “relations” with someone he should not and so uses the back door so no one sees him entering or exiting. Willie Dixon,
Howling Wolf, and The Doors have later used this term in equivalent meaning.