A vagina that hasn't been touched till the penis has fully penetrated the (an) anus continously. For then the the vaginas will then become a stenchy dirty "Sewer-Cave".
"Dude she let me put it in her ass, THEN I f***** her one pussy!"
"Awe damn, did you eat her out afterwards?"
"He'll no, that shit was a Sewer Cave when I was done with it"
The new class in the British class system, placed below the working class, which it has now effectively wiped out. The result of years of inbreeding and also often referred to as scum. The sewer class is now planning to destroy the Middle Class and Upper Class (the Old Guard) in order to become the dominant force in the United Kingdom. The sewer class must be stopped before England becomes a seething cesspit only catering to the needs of scum.
"With the best will in the world, you are sewer class". This sentence is usually accompanied by the Old Guard trying not to cringe themselves into shapes only considered to be attainable by a contortionist when seeing such atrocities.