Uhm ok, minds out of the gutter, please ;)

I was actually wondering about the origin of this phrase. I made a joke about it today and even though everybody had heard it (yup even the Germans) we didnt know if it was from a movie, song or other.
I tried searching on the net. It just seems to be a figure of speech and not an actual quote but I couldnt find any information on the origin. Does anyone know or has a site in English that I could try!?
Thank you!