This is the second time that Butters' has his own episode. The first was in "Butters' Very Own Episode".
Dr. Janus stands in front of Butters and stares at him for 2 hours before deciding to pee on him.
Stan, Kyle, Cartman and Kenny briefly appear, but have no dialogue in this episode.
Sherlock Holmes: Dr. Janus deciding to be Dr. Watson with Butters being Inspector Butters references this famous detective.
The name Dr. Janus is a reference to the Roman god of beginnings and transitions with the same name.
Depicted with two faces on the front and back of his head, this may also be a reference to the psychiatrist having multiple "faces" (personalities).
Dr. Janus staring at Butters in bed for two hours is from "Paranormal Activity" where Katie for some weird reason is staring at her boyfriend in bed.
At the end of this episode, Dr. Janus (aka, The Chinese Guy) is given a blanket by the officer and start talking to himself how he is not going to kill that fly on his hand and show the image face of Dr. Janus. This is a spoof to the original and remake of Alfred Hitchcock's "Psycho".