when sixty-nining your girlfriend while standing up you pile drive her with your penis in her mouth (Caution: It must be your girlfriend for full satisfaction).
A human being who places its lips upon the orifice of a dog's asshole and runs its tongue up the dog hole.
Check out the underground film titled "Variations on a Theme" -- there is a segment called "Rondo Cane" -- in that portion of the film (the last of that cinematic epic) the dog (a great dane) is on the floor, I go under it's tail and stick my tongue up the dogs' asshole as far as it will go.