Originating from the more commonly known "Filthball", A Filthpod refers to an even skankier, more whore-like rotten little knacker. However despite these clear flaws you would still ride them silly.
(While driving through a rough part of a city, looking out the window, passenger says to driver)
"jesus fuckin christ" "Look at that little filth-pod over there"
Reply: "Fuck!!!! Yeah she is a dirty little filth-pod alright"