Just like it says on here. This is a category in beastiality involving sexual intercourse between a dog and a human being. This can also be applied to sick, dirty humor. See below....
i.....wanna fuck a dog in the ass....i wanna fuck a dog in the ass...i wanna fuck a dog......i tried to fuck your mom in the ass...tried to fuck your dad in the ass...could only find the dog....and his ass...we wanna fuck a dog in the ass..we wanna fuck a dog in the ass..we wanna fuck a dog....i wanna fuck a pirate in the ass..argh me and me first mate you scurvy kerr...i wanna fuck a fuckin pirate but i found the dog....that was no dog that was thy own sister. -Jonathon Hasselmann; 12/20/2003
To dispose of goods, people or animals. Disposal does not need to be in a body of water.
Common usage in the mixed race culture in London, especially mixed black/irish.
Dean: I am a bad man
Harry: You're as bad as a cucumber Dean: I'd fuck a dog in a river.
Harry: ........ wait.... you'd fuck a dog in a river?.....
It is to emphasize the word "fuck." It comes from the shorter version of "give a fuck" and then "give a flying fuck." It means "I don't care" but with emphasis. So it is an emphatic "I don't care!" Or also, emphatic "I could care less."