There was a song in the "50s called "Goodnight Irene" There's a good chance the saying stemmed from that. I imagine that if you "Googled" it you could get the lyrics.
Although the song "Goodnight Irene" was popularised by Lead Belly in the 1940s it is said to have been based on a song written in 1886. The writer of the 1940s version admits that he based it on something that his uncle used to sing.
Best and latest version I've heard is by the late lemented Alex Harvey and the Sensational Alex Harvey Band. There was a BBC Radio2 tribute show recently and you may still get it on listen again